Preheat the oven to 375°F (190°C).
Place the hollowed bell peppers upright in a baking dish and drizzle the inside with 1 tablespoon of olive oil. Set aside.
In a large skillet, melt the butter over medium heat.
Add the minced garlic to the melted butter and sauté for 1-2 minutes until fragrant, stirring frequently to avoid burning.
Add the shrimp to the skillet and season with smoked paprika, crushed red pepper flakes, salt, and black pepper.
Cook the shrimp for 2-3 minutes on each side until they turn pink and are cooked through. Remove from heat.
Chop the cooked shrimp into bite-sized pieces and mix them in the skillet with the garlic butter sauce.
Remove half of the garlic butter shrimp mixture and set aside for topping later.
To the remaining shrimp mixture in the skillet, stir in the shredded mozzarella cheese, grated Parmesan cheese, and chopped fresh parsley until combined.
Spoon the shrimp and cheese mixture evenly into each prepared bell pepper.
Top each stuffed pepper with the reserved garlic butter shrimp pieces.
Cover the baking dish loosely with aluminum foil and bake in the preheated oven for 15 minutes.
Remove the foil and bake for an additional 5-7 minutes until the cheese is melted and the peppers are tender.
Remove from the oven and let cool for 5 minutes before serving.