Remove as much water as possible from the carrots and zucchini by squeezing them in a kitchen towel.
Add the first 9 ingredients (carrots through parsley) and 1 tablespoon basil and 1 teaspoon oregano to a large mixing bowl and mix with a wooden spoon until all incorporated.
Put the tomato paste, salt and pepper into the bottom of the crock cooker and stir to combine.
Prepare the peppers by removing the stems and seeds. Begin stuffing the peppers with the meat mixture, pressing the meat down with a spoon to pack tightly.
Place the stuffed peppers into the center of the crock cooker, avoiding the sides or they might burn.
Cover and cook on low for 4 hours.
Remove from the crock cooker and put into an oven-safe baking dish. Put mozzarella on the top of peppers. Place the pan of peppers under your oven broiler for 2-3 minutes, or until the cheese is melted and golden-brown.
Remove and serve with the tomato mixture from the bottom of the crock cooker warm.