1pound(450 grams) mushroomsany variety, such as button, oyster, porcini, or milk cap), halved if large
Juice of 1/2 lemon
Instructions
Place the butter, rosemary, garlic, and salt in a Dutch oven or large pot.
Cook on medium-low heat until the butter melts.
Add the mushrooms and reduce the heat to low. Cook, uncovered, until the mushrooms are creamy and have absorbed the butter, 30-40 minutes. (Don't allow the mushrooms to fry.)
Remove from the heat and allow to cool. Add the lemon juice.
Pack into jars or storage containers, along with any leftover liquid (you can also use it in place of regular butter in savory dishes).