Step 1
Preheat oven to 350 degrees F (175 degrees C). Line a large baking sheet with aluminum foil. Grease a 2-quart and a 1 1/2-quart round glass baking dish each with 3/4 teaspoon olive oil; drizzle 1 tablespoon of remaining olive oil into bottom of each baking dish.
Step 2
Bring a large pot of lightly salted water to a boil. Cook macaroni ziti farfalle and radiatore pasta in the boiling water stirring occasionally until cooked through but firm to the bite 8 to 10 minutes. Drain.
Step 3
Arrange sausage slices on foil-lined baking sheet.
Step 4
Bake sausage in the preheated oven until browned and crisp 30 to 45 minutes. Lower oven heat to 325 degrees F (165 degrees C).
Step 5
Beat eggs in a large bowl until foamy using an electric mixer. Add Pecorino-Romano cheese salt and black pepper; continue to beat egg mixture with electric mixer on highest speed until eggs and cheese are blended 2 to 3 minutes. Stir cooked pasta into eggs and cheese; mixture should be runny and look like pasta is floating in egg mixture. Stir additional beaten eggs and Pecorino-Romano cheese into mixture if more egg mixture is needed.
Step 6
Ladle spoonfuls of egg-pasta mixture into each casserole followed by a layer of sausage; continue layering pasta mixture and sausage until all sausage has been used. Top casseroles with final layer of pasta mixture. Drizzle top of each casserole with 1 tablespoon olive oil. Small pieces of pasta should stick out of the egg mixture.
Step 7
Bake in the oven until casseroles are set in the center about 1 hour; raise oven heat to 350 degrees F (175 degrees C) and continue baking until the tops of casseroles are browned and crispy 1 to 1 1/2 more hours.