Preheat oven to 350 degrees. Lightly grease a large casserole dish.
Puree the roasted red peppers in a food processor or blender until smooth. Set aside.
Heat 2 tbsp olive oil over medium. Saute the garlic, shallots, red pepper flakes, and oregano until fragrant, about 2-3 minutes. Swirl in the tomato paste and red pepper puree, then add vodka and cook until liquid reduces by about half, 5-8 minutes. Drop in the butter, then stir in coconut milk and 1/2 cup broth or water. Simmer about 8-10 minutes until sauce thickens. Taste for salt and pepper. Finally, stir in the basil.
Meanwhile, heat a large pot of salted water. Boil the jumbo shells according to package directions. Drain.
When ready to assemble, make the filling. In a bowl, stir the ricotta, parmesan, provolone, about 1/2 cup of pesto sauce, spinach, and a pinch of salt and pepper until well incorporated.
Spread about half of the roasted red pepper sauce into the bottom of the casserole dish. Spoon about 1 tbsp filling into each shell and nestle into the dish. Repeat with remaining shells. It is okay if the shells overlap a bit and crowd the pan!
When all the shells are filled, pour the rest of the red pepper sauce overtop. Drizzle pesto, then arrange torn mozzarella bits evenly across the shells. Bake 20-25 minutes until cheese bubbles. Remove from oven and top with additional chopped basil as desired.