1 lb. Shiitake mushrooms, stems removed
2 Tbsp. butter
1 small onion
1 tsp. salt
1 tsp. sugar
1 Tbsp. soy sauce
1½ c. pounds salted butter, softened
Tear up a pound of de-stemmed Shiitake. You'll be cooking these down and pureeing them, so large pieces are okay.
On medium heat, melt 2 Tbsp. butter in a medium skillet and add 1 small chopped onion and sauté until soft. Add mushroom pieces, stir around a bit and cover the pan. Every few minutes, check the pan and stir things around, keep the heat warm enough to cook the mushrooms but try to avoid browning the onions. Once the mushrooms start to cook down and you see a liquid at the bottom of the pan (about 5-10 minutes) add the salt and sugar. Reduce the heat and keep stirring things around every few minutes until the cloudy liquid at the bottom of the pan starts to become clear. Remove the lid and add the soy sauce and cook a few minutes more, then remove from heat.
Let the mixture (duxelles) cool until it reaches room temp. Stir things around in the pan to aid in even cooling. Once the mushrooms are only slightly warm to the touch, puree in a food processor until the mixture is a paste.
(b)The secret to making an excellent shiitake butter? Make sure EVERYTHING, especially the ingredients and mixing bowl, is at room temperature for this final blending of mushroom puree and butter!
Measure out your puree and ready an equal amount of medium soft butter. The puree volume can vary depending on the raw mushrooms moisture content, but it should be around 3 cups. Whip or beat the butter till fluffy mixer using a mixer outfitted with a whip attachment (if you don't, regular beaters will do). Then stir in the puree, finally whipping it, until the butter and mushrooms are well blended. This is the secret to making a consistent, well blended butter. If components are too warm, you'll end up with soup; if they're too cool, you'll end up with chunky butter.
This recipe makes about 3 lbs. Shiitake butter. Transfer to individual deli containers or jars for gifting, or wrap in freezer paper. This recipe can be doubled using a standard 4 ½ qt. mixing bowl.