Two pounds of ricotta
If it was a 3lb container, and you only used a pound of it, do what I do. Take the original container with the remaining 2lbs of ricotta, put the lid on it, and put it in a ziploc freezer bag. Then freeze it just like that. When you want to make the casserole again, just defrost the container and refreeze whatever you don't use. The ricotta is very forgiving. Its consistency changes slightly by the third usage, but the taste remains exactly the same. Remember to use a ziploc bag and seal the air out. That's important.
2 pounds ricotta cheese
2/3 cup white sugar
1/3 cup all-purpose flour
1/4 teaspoon ground cinnamon
2 teaspoons orange zest
2 teaspoons vanilla extract
1/8 teaspoon salt
Preheat oven to 300 degrees F (150 degrees C). Set rack in the middle of the oven. Butter and flour a 9 1/2 inch springform pan, and tap out excess flour.
Place the ricotta in a large mixing bowl, and stir it as smooth as possible with a rubber spatula. Stir the sugar and flour together thoroughly into the ricotta. Stir in the eggs 1 at a time. Blend in the vanilla, cinnamon, orange zest, and salt. Pour batter into the prepared pan.
Bake in the center of the oven for about 1 1/4 to 1 1/2 hours, until a light golden color. Make sure the center is fairly firm, and the point of a sharp knife inserted in the center comes out clean. Cool on a wire rack. It will sink slightly as it cools. Cover, and chill till serving time.