Heat olive oil in a skillet over medium heat.
Sauté thinly sliced onion, red pepper, and finely chopped garlic until they are crisp-tender.
Add the sliced pepperoni, dried basil, dried oregano, Italian seasoning, garlic powder, salt, and pepper.
Cook, stirring occasionally, for about 5 minutes.
Stir in the cooked tortellini pasta and continue cooking until the mixture is heated through.
Garnish with shaved Parmesan cheese and fresh basil.