Preheat the oven to 350ºF. Heat a large pot of water to a boil, toss in rigatoni and cook for 10 minutes. Drain and set aside.

In a medium sauce pan, heat 1 tablespoon of olive oil to medium. Add in the diced onion and minced garlic. Let cook for 5 minutes until they begin to brown. Remove from the pan.

Add the remaining 3 tablespoons of olive oil to the pan. Toss in the sage leaves and saute until they begin to crisp up. Remove from the oil and let drain on a paper towel.

Stir in the flour and whisk until smooth. Let bubble and thicken for 2 minutes. Stir in the cornstarch, then slowly begin to incorporate the milk and beer.

Then add in the pumpkin puree, nutritional yeast, dijon mustard, garlic powder, onion powder, red pepper flakes, cayenne, salt and black pepper. Let the sauce simmer and thicken for 15 minutes, whisking occasionally.

Once sauce has thickened a bit, slowly add in the provolone cheese and half of the cheddar. Let thicken another 5 minutes.

Add the drained pasta back into the large pot. Toss in the diced bratwurst and sauteed onions. Pour the cheese sauce over and mix well.

Place the pretzels into a small baggie, and crush using a kitchen mallet or rolling pin.

Pour the pasta into a 13 x 9 pan, sprinkle the crispy sage, crushed pretzels and the rest of the shredded cheddar cheese. Bake for 25 minutes.