J:

I made lasagna twice in the past couple of months. Both times
were birthday requests. Since my earlier recipe doesn't really
give amounts, I paid closer attention so you (or me, next time)
don't have to prepare a bunch of stuff and then just keep
assembling until you run out of one thing or another. That
always makes for a lot of leftovers of one ingredient.

See also Lasagna in an earlier recipe.

So I guess I'll try to give the whole recipe here, but with
actual amounts, where I know them. This makes a big batch.

20 oz spinach (*)
1 bunch fresh basil (optional)
3 pounds ricotta
1 egg
salt and pepper to taste
2 pounds mozzarella, shredded
4 quarts marinara (**)
2 pounds dried lasagna noodles (35 "sheets")
1/2 cup parmesan, shredded or grated

Steam spinach until just cooked. Cool, drain, and squeeze lots
of water out of it. In a food processor, blend the spinach,
basil if you're using it, and about two cups of the ricotta
until they are a smooth paste. Empty into a big bowl with the
rest of the ricotta, the egg, and salt and pepper to taste.
Mix well.

Preheat oven to 375 degrees.

In an 11x17 inch baking or roasting pan, ladle some of the
sauce. With a knife or spatula, spread ricotta mixture on some
lasagna noodles, covering them completely. Arrange a layer of
noodles side by side in the pan, ricotta side up. Add more
sauce, about three ladles full. It should cover the noodles
thinly, but not be running all down the sides and between the
cracks of the noodles. Sprinkle with mozzarella. Repeat,
adding a layer of noodles, sauce, and mozarella, until the
everything is used up, except a few cups of sauce. I get seven
noodles to a layer and 5 layers. You shouldn't have so much
sauce that everything is submerged, but a few bottom layers
probably will be. Sprinkle the parmesan on top. Cover tightly
with foil and bake for 1 hour. Remove from the oven and let
"set" for at least 20 minutes. Cut and serve with remaining
sauce, heated.

You can scale down this recipe as follows. I get three layers
of six noodles in a 15x10 inch baking pan.

10 oz spinach
1 bunch fresh basil (optional)
1 pounds ricotta
1 egg
salt and pepper to taste
1 pounds mozzarella, shredded
2 quarts marinara
1 pounds dried lasagna noodles (18 "sheets")
1/4 cup parmesan, shredded or grated

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(*) I buy two 10 oz bags of pre-washed spinach but anywhere in
the 1 - 1 1/2 pound range will do.
(**) I won't give that recipe here, you've seen it before.