1 pkg. frozen chopped spinach
3/4 cup grated parmesan
1 1/2 cup shredded mozarella
2 Tbsp. butter
1 box manicotti shells (usually 14 shells)
Cook the shells until center of pasta is a little firm, not hard. Drain. I rinse in cool water and then lay out on a linen towel to dry.
Cook spinach as directed, save liquid. Brown ground beef, drain, add 2 Tbsp. butter (I omit), 1/2 tsp. salt, and 1/4 tsp. pepper. When spinach is cool, squeeze out liquid and add to meat, continue cooking for 3 minutes.
Turn off heat. Beat 4 eggs in a bowl and add the parmesan. Blend into meat well, and then fold in the mozarella. Stuff the manicotti. Spread your favorite tomato sauce into glass casserole.
You can make this filling for stuffing shells instead of manicotti, and also use as a layer in lasagna. Filling can be made ahead, or assemble (but do not add sauce until ready to bake) and cover a day before serving. If assembled, take out of fridge an hour before baking.