Slow Cooker Italian Sausage and Peppers

Ingredients

• 1 14-ounce can cherry tomatoes, such as Corbara
• 2 tablespoons tomato paste
• 1 red pepper (thinly sliced)
• 1 yellow pepper (thinly sliced)
• 1 red onion (peeled and thinly sliced)
• 2 garlic cloves (smashed and peeled)
• 1 tablespoon olive oil
• 1/2 teaspoon kosher salt
• 1/2 teaspoon dried oregano
• 2 pounds raw spicy Italian sausages (about 8 sausages)
• 1 2inch piece parmesan cheese rind
• 1/4 cup basil leaves (chopped)
• 1/2 cup freshly grated parmesan cheese (optional)