In a skillet, cook sausage and beef over medium-high heat, breaking up the meat as it cooks. Cook until fully cooked.
Add in onion, red pepper, and garlic, season with salt and pepper to taste. Allow the vegetables to cook for 3-5 minutes until onion is soft and translucent.
Stir in tomato paste, tomatoes, and Italian seasoning; bring to a boil, then remove from heat.
Using a measuring cup add 2 cups meat mixture into bottom of slow cooker. Layer 3 lasagna noodles (uncooked), top with 2 cups of meat mixture and then 1/2 cup of cheese.
Repeat noodles and meat for two more layers.
Set slow cooker on low, cover and cook for 4-6 hours. Once done cooking, sprinkle lasagna with cheese, return the lid and cover until cheese has melted.
As for dessert, Marie Callender's takes special care to make each pie look and taste homemade. By using fresh ingredients like hand-picked blackberries and tried and true recipes, each pie will taste like you made it from scratch.