Compound Butter with Mushrooms and Walnuts

Steep mushrooms in warm cream first. That’s where the whole thing starts. Everything else is just technique.

Why You’ll Love This Compound Butter

Takes 40 minutes total—18 to prep, 22 if you count the resting. Flavor comes from actual ingredients, not from jarred stuff you can’t pronounce. The mushroom infusion gives it depth that regular herb butter doesn’t touch. Walnuts add texture—a little crunch that catches you. Works on steak, works on turkey, works on literally anything hot. Made at home means you know exactly what’s in it. Smoked salt shifts the whole thing. Not overwhelming. Just there.

What You Need for Homemade Compound Butter

Cream—140 ml of it, 35% fat minimum. Lower fat and it won’t separate right. Dried wild mushrooms, finely chopped. Five grams. Not much but it matters. Toasted walnuts, 50 ml chopped. Toast them yourself in a dry skillet—three minutes, watch them constantly or they burn and taste like charcoal. Fresh tarragon, 12 ml minced. Not dried. The fresh stuff has a brightness dried can’t match. Smoked sea salt. Just a pinch. Freshly ground black pepper. That’s it.

How to Make a Flavored Butter from Scratch

Heat the cream with mushrooms in a small saucepan until it bubbles at the edges. Not a rolling boil. Just bubbles. Pour it into a bowl, cover it tight, let it sit until it’s warm to the touch—around 25 minutes. Don’t rush this. The mushrooms soften and infuse everything with this deep, earthy thing that tastes slightly bitter in the best way. The smell alone tells you when it’s working.

Add cold cream to the mushroom liquid. Beat it with an electric mixer on medium-high. Eight to ten minutes. You’re waiting for curds to form, for the butterfat to actually separate from the buttermilk. It happens. You’ll see clumps pulling away from the liquid, getting grainy. Don’t overbeat or the whole thing goes greasy and won’t come back. Stop when it looks curdled. Seriously.

Drain the whey through a fine sieve lined with cheesecloth or a clean tea towel. Press gently. Squeeze out as much liquid as you can. Let the butter sit on a paper towel to catch whatever’s left. This is the difference between spreadable and watery.

How to Get Compound Butter Right

Transfer the butter to a mixing bowl. Fold in the walnuts and tarragon. Not stirring aggressively. Folding. The walnuts stay intact that way, keep their crunch. The tarragon spreads through evenly. Season it now—smoked salt, black pepper. Taste it. Salt levels vary. Some smoked salt hits different than others. Adjust.

Shape it into a log on parchment or plastic wrap. Roll it tight. Press the seams together so no air gets trapped. Chill for at least an hour. It gets firm but still spreadable. Flavors marry. Butter solidifies without getting hard. Then you slice it, melt it over steak, over turkey, over roasted potatoes. Whatever.

Compound Butter Tips and Common Mistakes

Dried wild mushrooms aren’t all the same strength. Some are intense, some are mild. Adjust the amount or the steeping time depending on what you have. Don’t steep longer than 30 minutes or bitterness creeps in and ruins the whole thing. Toast walnuts in a dry skillet over medium-low heat, stirring often, until fragrant with faint smoke. About three minutes. They burn fast. Watch them.

Tarragon could swap for chives if you want—sharper, anise-note contrast. Use less though. Smoked salt could be fleur de sel instead, but the smoky echo is the point. Plain sea salt works. Fresh herbs matter. If you only have dried tarragon or parsley, use less. Dried is concentrated and tastes different.

Don’t skip the whey draining step. Too much moisture makes the butter soft, wrecks the spreadability, shortens how long it lasts in the fridge. Wrap it tight so it doesn’t absorb fridge smells. Hand whisking works if you don’t have a mixer but it’s exhausting. You’ll know when to stop—curdled texture, liquid separating.

Cream needs 35% fat minimum or the separation doesn’t happen. Fresh cream works better than cream that’s been sitting. If it’s too cold, whipping takes forever. Room temperature helps it along.

Compound Butter with Mushrooms and Walnuts

By Emma

Prep:

18 min

Cook:

22 min

Total:

40 min

Servings:

4 servings

Ingredients

• 140 ml 35% cream
• 5 g dried wild mushrooms, finely chopped
• 50 ml walnuts, toasted and chopped
• 12 ml fresh tarragon, minced
• Pinch smoked sea salt
• Freshly ground black pepper

Method

1. Preparation
2. 1 Heat 140 ml cream and chopped wild mushrooms in a small saucepan until it just bubbles at edges; no rapid boil or it scorches. Pour into a bowl, cover tightly; let steep until warm to the touch, about 25 minutes. The mushrooms soften, infusing a deep, earthy aroma with a subtle bitterness. Don't rush this phase; flavor extraction matters.
3. 2 Add remaining cold cream to mushroom-infused liquid; chilling cream beforehand helps maintain whipping integrity. Beat mixture with electric mixer at medium-high until curds form and butterfat separates from buttermilk. Expect about 8 to 10 minutes. Watch for grainy curds pulling away from liquid, clumps coalescing. Don’t overbeat or it’ll get greasy.
4. 3 Drain off liquid whey through fine sieve lined with cheesecloth or a clean tea towel. Press gently to expel as much liquid as possible. Let butter rest on paper towel to drain excess. This ensures a firmer, spreadable butter rather than watery slop.
5. Finishing
6. 4 Transfer butter into mixing bowl. Fold in toasted walnuts and minced tarragon. Walnuts add toasted crunch, tarragon brightens with herbal tang. Season with smoked sea salt and black pepper to bring layers of flavor and seasoning balance. Taste as you go — salt levels vary widely; smoky salt shifts flavor depth differently than regular.
7. 5 Shape butter into a rough log on a sheet of parchment or plastic wrap. Roll tightly, pressing seams to seal air. Chill at least 1 hour until firm but still spreadable. This allows flavors to marry and butter to solidify without hardening. Ready to slather on crusty bread or melt over meats.
8. Tips & Tricks
9. 6 Dried wild mushrooms vary in strength; adjust steeping and amount depending on type. Avoid soaking in hot cream longer than 30 minutes; bitterness creeps in. Toast walnuts in a dry skillet over medium-low, stirring often until fragrant with faint smoke, about 3 minutes. Watch carefully — nuts burn fast, ruins flavor.
10. 7 Tarragon swaps for chives offers sharper, anise-note contrast but use sparingly. Smoked salt replaced fleur de sel for subtle smoky echo but plain sea salt works. If fresh herbs unavailable, reduce amount or substitute fresh parsley or tarragon flakes dried (less pungent).
11. 8 Don’t skip draining liquid whey. Too much moisture makes the butter soft, impacts spreadability and shelf life. Refrigerate butter tightly wrapped to prevent absorbing fridge odors.
12. 9 If electric mixer not at hand, vigorous hand whisking possible but laborious. Visual cues for butterfat separation include curd-like, clumpy texture detaching from thin watery liquid.
13. 10 Use cream with 35% fat minimum; too low fat won’t separate efficiently. Fresh cream beats better than older cream nearing expiration. If cream too cold, whipping slows dramatically; room temp helps.
14. 11 Works well as finishing butter for grilled meats, steamed veggies, or stirred into creamy risottos. Also divine melting hot over roasted potatoes.

Nutritional information

Calories

140

Protein

1g

Carbs

1g

Fat

15g

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Frequently Asked Questions About Compound Butter for Steak

Can you make compound butter without an electric mixer? Yeah. Hand whisking works but your arm gets tired fast. Takes longer—maybe 15 minutes instead of 10. Visual cue’s the same though. Curds form, liquid separates. You’ll see it.

How long does homemade compound butter last? Wrapped tight in the fridge, goes three to four weeks. Freezer, longer. Months. The whey draining matters here—too much moisture and it gets funky faster.

Can you substitute the tarragon for something else? Chives work. Parsley. Even just the mushrooms and walnuts alone is good. Tarragon’s bright but not mandatory. Fresh beats dried though. Dried tarragon tastes like straw.

What’s the best way to use this as a finishing butter for steak? Slice off a piece, drop it on the hot meat right when it comes off heat. It melts into the cracks and pools. Also works on turkey, grilled vegetables, roasted potatoes. Honestly works on everything.

Does the mushroom flavor stay strong after the butter chills? It does. Actually gets deeper. The flavors marry while it sits. First hour it’s subtle. After that it intensifies. That’s why the chilling matters—not just for texture.

Can you use fresh mushrooms instead of dried? Not the same. Fresh are mostly water. They’d need to cook down first and you’d lose half the mushroom. Dried is concentrated. That’s the whole reason to use them. Porcini butter specifically—porcini mushrooms are intense, use half as much.