Bring a large pot of salted water to a boil over medium-high heat. Add fusilli pasta and cook according to package instructions (8-10 minutes). Drain and set aside.

In a large skillet, heat vegan butter over medium heat. Add diced onion and cook for about 4 minutes until soft and translucent. Stir in minced garlic and cook for an additional 2 minutes until fragrant.

Incorporate sliced baby bella mushrooms, stirring to combine. Cook for about 5 minutes until the mushrooms soften and release their juices.

Add another tablespoon of vegan butter and allow it to melt completely. Sprinkle in spelt flour, stirring for 1-2 minutes until the mixture becomes sticky. Gradually pour in soy milk, whisking continuously until creamy and smooth (3-5 minutes).

Stir in dried oregano, nutritional yeast, salt, and pepper to taste. For a kick, add a pinch of cayenne pepper. Mix well for about 1-2 minutes.

Fold in frozen peas and drained pasta into the creamy sauce, stirring gently. Cook for an additional 4-5 minutes until warmed through and peas are bright green.

Taste and adjust the seasoning as necessary. Add extra salt, pepper, or cayenne to enhance the flavors.

Spoon generous portions onto plates and garnish with dried oregano or crushed red pepper before serving.