In a large bowl, combine the peeled and deveined shrimp with onion powder, garlic powder, cayenne pepper, and salt. Mix thoroughly until all shrimp are well coated.

Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the seasoned shrimp and cook for about 1 minute on each side, or until pink and opaque.

Reduce the heat to medium and pour in the remaining tablespoon of olive oil. Add sliced onion and chopped serrano pepper, sauté for about 3-4 minutes.

Add minced garlic and cook for an additional minute, stirring constantly.

Stir in chopped Roma tomatoes and cover the skillet. Cook for 5 minutes over medium heat until tomatoes are soft.

Return the cooked shrimp to the skillet and cook together for another 3-4 minutes until shrimp are fully cooked.