Bring a large pot of water to a boil. Add shells to the pot and cook according to package instructions. Drain and rinse with cold water. Set aside.
Heat olive oil in a pan over medium heat. Add sausage and crumble with a wooden spoon. Continue cooking until browned (approx. 5 minutes).
Add onion, garlic, oregano, dried basil a pinch of salt, pepper & red pepper flakes to the pan. Sauté until onions are cooked through (approx. 5-7 minutes).
Add the pumpkin puree, tomato paste and broth to the pan and stir to combine. Add the non-dairy milk and give it one last mix. Remove the sauce from the heat and set aside until ready to use. Prepare the vegan ricotta according to the instructions. Add the ricotta, spinach, sun-dried tomatoes, fresh basil and a pinch of salt and pepper in a bowl. Stir until combined.
Preheat oven to 350 degrees.
Spread 1 cup of sauce on the bottom of a baking dish (I used a 10" cast iron skillet). Fill each shell with about 1 tbsp of the ricotta mixture and place in the baking dish. Repeat until all of your filling is used. Spread the remaining sauce across the top of the shells. Place in the oven for 15-20 minutes, or until warm and bubbly.
While the shells are cooking, prepare the fried sage. Heat vegan butter in a small sauce pan. Add fresh sage leaves to the pan and cook until crispy. Remove from the pan and place on a paper towel to absorb leftover butter.
Once the shells are done baking, top them with the fried sage and fresh thyme. Serve while hot and store leftovers in an airtight container in the fridge.