Pumpkin Pasta Sauce: Melt the vegan butter in a large skillet. Add in the thyme leaves, grated garlic, ground cinnamon, ground nutmeg and chili flakes. Cook for 1-2 minutes. Mix in the all-purpose flour and cook for 1-2 minutes, while stirring to prevent burning. Stream in the oat milk, and with your other hand, mix together. Once it becomes thick, mix in the vegan cheese, black pepper, salt and pumpkin puree. Pour in the veg broth, mix, and cook for 10 minutes. Stirring often.
Tofu Pesto Ricotta: Add the block of tofu, nutritional yeast, apple cider vinegar, garlic cloves, mustard powder, onion powder, salt and black pepper into a food processor. Blend until combined. Transfer into a bowl, and dollop 4-6 tbsp of the basil pesto over the tofu ricotta. Mix together 3-4 times to create swirls.
Pasta shells: Follow the directions on the packaging of the pasta. Drain the water.
Final touches: Stuff the cooked pasta shells with the pesto ricotta and place into the skillet with the pumpkin pasta sauce. If you didn't use a skillet, simply transfer the sauce into a baking dish, then add the stuffed shells. Dollop 2-3 tbsp more of the basil pesto over, and top with vegan cheese. To help the vegan cheese melt, sprinkle a little water over the cheese. Bake for 20 minute. Serve with loads of fresh basil.