6 ounces (1-1/2 sticks) unsalted butter
1 cup (loosely packed) fresh mint leaves
1 large clove garlic or 2 small ones, crushed and peeled
Juice of 2 lemons (about 1/4 cup)
Sugar
Salt
Melt butter over low heat. When just melted, remove from heat and set aside to cool. Place mint leaves, garlic, lemon juice, a large pinch of sugar and a small pinch of salt into the bowl of a food processor with steel blade. Pulse until leaves and garlic are finely chopped. With motor running, slowly pour in butter in a thin stream, as if you were making mayonnaise. When all the butter is added the sauce is smooth, turn off machine, taste and adjust sugar and salt if necessary. Pulse to incorporate extra seasonings if you added them, then let sauce stand at least 10 minutes. Butter should start to solidify. Just before serving, turn on machine and whip until fluffy and smooth.
Makes about 1 cup.
NOTE:
This can be made ahead, but is at its best when fresh. Keeps up to a week in the refrigerator. Let stand at room temperature until softened, then whip briefly with a fork just before serving.