Blanch collard greens for 2 minutes in boiling water, until they start to darken in color. Drain and set aside.
Saute' tempeh and garlic for 3-4 minutes over medium heat or until browned. Reduce heat to medium-low and add fennel seeds, paprika and chile flakes. Continue to cook for 3-4 minutes, until fragrant, stirring frequently. Transfer tempeh to a bowl and return pan to heat.
Increase heat to medium-high, and saute' onion for 2-3 minutes. Add tempeh mixture, stir to combine, and add spaghetti sauce and oregano. Allow to simmer for a few minutes, then add collard greens. Finally, add the penne and mix it all together.
Recipe by Super Veggie Mom at https://superveggiemom.com/recipe/vegan/meatless-sausage-penne-with-greens/