Butternut Squash Rigatoni Gratin with Leek

Roast the squash first while the oven’s still heating up — it’s the longest part and might as well run. Three-quarters of an hour total, most of that hands-off. Pasta, leeks, a roux, two cheeses melted on top. The kind of thing you put in a baking dish and forget about while it bubbles.

Why You’ll Love This Butternut Squash Pasta Gratin

Tastes like fall but doesn’t need three trips to the farmer’s market. Roasted squash gets sweet. Leeks go soft. Sharp cheddar doesn’t disappear into the sauce — it crisps up on top. One dish to roast, one to boil pasta, one to make the sauce. That’s it. No stockpot circus. Works as dinner by itself. Works as a side for ham, for roasted chicken, for nothing — just the gratin alone is enough. Leftovers reheat fine. Actually better the next day when flavors have sat overnight and gotten to know each other. Comfort food that’s technically vegetables. The spinach melts in. Nobody notices it’s there.

What You Need for Butternut Squash Rigatoni with Cheddar

Butternut squash. About three and three-quarter cups, peeled and cut into chunks — not too small or they’ll collapse, not huge or they’ll still be hard when the pasta’s done. Olive oil. Just to coat the sheet pan. Rigatoni. Dried is fine. The tube shape catches the sauce instead of letting it slide off. Three-quarter pound or so. Leeks. Two medium ones, sliced. The white and light green parts. Dark green goes in the compost. You need about three cups. One small onion and two garlic cloves. Minced. Adds backbone without being obvious. Butter and flour for the roux. A quarter cup of each. Whole milk and chicken broth — two cups and a cup and an eighth. The ratio matters because too much liquid and it never sets; too little and it’s like wallpaper paste. Fresh spinach. Seven cups. Sounds like a lot. It’s not — wilts down to almost nothing. Sharp cheddar and Parmigiano Reggiano. Seven-eighths cup and just over half a cup. The sharp cheddar’s the main event. Parmigiano adds nutty undertone. Don’t use mild cheddar. Defeats the purpose. Salt, pepper. Red chili flakes if you want heat. Nutmeg — just a dusting. Optional but it works.

How to Make Butternut Squash Rigatoni with Spinach and Cheese

Oven to 410. Middle rack. Parchment on a sheet pan.

Squash chunks go on the pan. Drizzle olive oil. Salt and pepper. Toss it around so everything’s coated. Twenty-two minutes in, stirring halfway through. You want the edges golden and the insides soft enough to push through with a fork. Don’t leave it in longer or it turns to mush and loses flavor. It’ll still cook a bit more in the gratin anyway.

While that’s roasting, get a large pot of salted water boiling. Rigatoni goes in. Cook it one minute less than the box says — it should have a bite still, not be done done. Drain it. Drizzle a tiny bit of oil so it doesn’t weld itself together. Cover it. Keeps warm.

Same pot. Melt butter over medium heat. Add the sliced leeks, chopped onion, minced garlic, and a pinch of salt. This is the sweating stage. Eight minutes, maybe nine. You want everything translucent and soft. Not brown. Brown tastes bitter and you don’t want bitter here.

Sprinkle the flour over. Stir for a minute. Get the raw flour taste out.

Whisk in the chicken broth and milk slowly. Sounds boring. It’s the difference between lumpy sauce and smooth sauce. Once it’s all in, turn up the heat slightly. Let it come to a soft boil. Then lower the heat and let it bubble gently for about six minutes. Watch the spoon — when the sauce coats it and doesn’t immediately run off, it’s thick enough. Should feel like heavy cream, not like soup.

How to Get Butternut Squash Pasta Gratin Creamy and Perfect

Off heat now. This is where the immersion blender comes in. You’re making the leeks disappear into the sauce. Run it until it’s totally smooth. Chunks in there and the texture gets weird and grabby. So blend it till it’s like velvet.

Fold in the roasted squash. Fold in the pasta. The spinach goes in last and while everything’s still hot it’ll wilt down to nothing. If you add it cold, it tastes grassy and slightly bitter. You don’t want that. So wait.

Taste it. Fix the salt and pepper. The chili flakes and nutmeg do something strange and good — they add warmth without tasting spicy or nutmeggy. Optional but try it once.

Spread it all into a 13-by-9 baking dish. Level the top a little. Cheddar and Parmigiano go all over. Be generous. The cheese is the whole point — without it, you’ve just got hot pasta in a dish.

Oven for 24 to 27 minutes. The cheese bubbles. The edges crisp. You’ll hear a tiny crackle when the top browns. That sound means it’s done. Too long and the sauce dries out underneath. Too short and the cheese is melted but the sauce is still loose.

Let it sit for fifteen minutes before you eat it. The sauce sets. The pasta absorbs what’s left. It all comes together.

Use a metal spatula. Scrape the bottom. That’s where the crispy bits are — that’s the reward.

Butternut Squash Pasta Gratin Tips and Common Mistakes

Overcooked pasta is the death of this. It turns gummy inside the gratin. Cook it a minute under what the box says. Seriously.

If your sauce is too thick before it goes in the oven, splash in a bit more milk or broth. If it’s too thin, simmer it another couple minutes. You want it to flow a little but not slosh.

The squash should be tender when you take it out but still hold its shape. If it’s mushy, it won’t puree right and the roasted pieces fall apart. If it’s hard, the gratin won’t feel done and the flavor stays stuck inside.

Roast the squash and boil the pasta at the same time. Everything’s ready at once instead of you standing around waiting. Way faster.

The spinach is weird because you prep it ahead but add it right at the end. It’s worth doing it that way.

Butternut Squash Rigatoni Gratin with Leek

By Emma

Prep:

30 min

Cook:

50 min

Total:

1h 20min

Servings:

8 to 10 servings

Ingredients

• 900 ml (3 3/4 cups) butternut squash peeled, seeded, cut into chunks
• 30 ml (2 tbsp) olive oil
• 380 g (about 3/4 lb) rigatoni pasta
• 700 ml (about 3 cups) sliced leeks (1 to 2 medium-sized)
• 1 small onion, finely chopped
• 2 garlic cloves, minced
• 60 ml (1/4 cup) unsalted butter
• 65 ml (1/4 cup plus 1 tsp) all-purpose flour
• 475 ml (2 cups) chicken broth
• 275 ml (1 1/8 cups) whole milk
• 1.8 liters (about 7 cups) fresh baby spinach, stemmed and roughly chopped
• Pinch red chili flakes (optional)
• Grated nutmeg, a light dusting (optional)
• 220 ml (7/8 cup) shredded sharp cheddar cheese
• 130 ml (just over 1/2 cup) grated Parmigiano Reggiano
• Salt and pepper

Method

1. 1 Set oven rack to middle position. Preheat oven to 210 C (410 F). Line baking sheet with parchment paper.
2. 2 Scatter squash cubes on sheet. Drizzle olive oil, season with salt and pepper; toss to coat evenly. Roast about 22 minutes, stirring halfway, until tender, golden edges forming. Don’t overcook or squash loses shape and flavor goes flat. Let cool.
3. 3 Meanwhile, bring large pot of salted water to boil. Cook rigatoni just under al dente — firm with slight bite — drain, drizzle a touch of oil to prevent sticking. Set aside covered to keep warm.
4. 4 Use same large pot. Melt butter over medium heat. Add leeks, onion, garlic; sweat gently with a pinch salt till translucent, about 8 minutes. Don’t brown—no bitterness. Sprinkle flour evenly, cook stirring for 1 minute to get rid of raw taste.
5. 5 Gradually whisk in chicken broth and milk. Bring to soft boil, then reduce heat and simmer until sauce thickens, bubbles coat spoon, about 6 minutes. Sauce should be creamy, not too thick or thin. Taste for seasoning.
6. 6 Remove from heat. Use immersion blender for smooth leek purée. Don’t leave chunks—they create uneven texture. Fold in roasted squash, cooked pasta, and chopped spinach while still warm. Spinach wilts gently in residual heat—if you add raw, it tastes grassy and bitter.
7. 7 Adjust seasoning—salt, pepper, and optional chili flakes and nutmeg. These add surprising warmth and lift. Mix well but gently, keep pasta intact.
8. 8 Transfer mixture to 33 x 23 cm (13 x 9 inch) ovenproof dish. Spread evenly. Top with cheddar and Parmigiano. Cheese blend gives sharpness and nutty crust. Don’t skimp or gratin lacks character.
9. 9 Bake for 24 to 27 minutes until cheese bubbles and develops golden-brown spots. Edges crisp up—listen for slight crackle. Overbaking dries it; underbaking leaves sauce runny. Let rest 15 minutes before serving to set. The gratin firms, flavors meld.
10. 10 Serving tip: spoon out with metal spatula scraping crispy cheese bits underneath. Perfect alongside simple salad or roasted ham.
11. 11 Substitutions: Swap chicken broth for vegetable broth for vegetarian option. Use Gruyère or Fontina in place of cheddar for a milder cheese note. If you want vegan, replace butter with plant-based margarine and milk with unsweetened oat milk; omit cheeses or use vegan alternatives though texture will differ.
12. 12 Common issues: Overcooked pasta turns gummy—always undercook by a minute or two. If sauce too thick before baking, thin with splash more milk or broth; too thin, simmer longer to reduce. Squash should be fork-tender but hold shape—mushy cubes won’t roast well or puree smoothly.
13. 13 Efficiency tip: Roast squash and cook pasta simultaneously to cut total time. Prepare sauce while those roast and boil. Saves waiting around, gets everything hot and ready faster.

Nutritional information

Calories

320

Protein

15g

Carbs

38g

Fat

14g

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Frequently Asked Questions About Butternut Squash Pasta Gratin

Can I make this ahead and bake it later? Yeah. Assemble it in the dish, cover it, stick it in the fridge. When you’re ready to eat, add maybe two or three extra minutes to the bake time since it’s cold. Or let it come to room temperature first if you want it to bake faster.

What if I don’t have an immersion blender? Regular blender works. Do it in batches so it doesn’t explode everywhere. Or just mash it with a fork if you don’t mind some texture. Not ideal but it works.

Can I use frozen squash? Probably. Thaw it first, drain it really well or it’ll be watery. Won’t roast the same way — you’re looking for crispy edges. Might be softer. Still tastes fine.

Is there a vegetarian version? Use vegetable broth instead of chicken broth. Everything else stays the same. The cheeses are already in there so it’s fine.

What cheese should I use if I don’t have sharp cheddar? Gruyère works. Fontina works. Both are milder and slightly nutty. Don’t use mild cheddar. Doesn’t have the backbone. Parmesan on top is fine either way.

How long does it keep? Three or four days in the fridge. Reheat it at 350 degrees, covered, for about ten minutes. It dries out if you go hotter or longer. Doesn’t freeze well — the sauce gets weird and separates.