CREAMY SPINACH
AND MUSHROOM
LASAGNA
NOTE: The mushrooms can be chopped with a knife.
Alternatively, break them up with your fingertips, or
pulse them in a food processor. They should be chopped
until no pieces larger than ¼ inch remain.
SERVES 6 TO 10
8 tablespoons (1 stick) unsalted butter, plus more for
greasing the baking dish