Instructions:

Prepare the Peppers: Preheat oven to 375°F (190°C). Cut bell peppers in half lengthwise, remove seeds and membranes. You can also slice a thin piece off the bottom of each pepper half to help them stand upright.
Cook the Filling: In a large skillet over medium-high heat, brown the ground beef, breaking it up with a spoon. Drain off any excess grease.
Add Flavor: Add the chopped onion to the skillet and cook until softened, about 5 minutes. Stir in the minced garlic and cook for another minute until fragrant.
Season: Stir in the Worcestershire sauce, mustard, smoked paprika, salt, and pepper.
Assemble: Place the bell pepper halves cut-side up in a baking dish. Fill each pepper cavity with the ground beef mixture.
Cheese and Bake: Top each stuffed pepper with shredded cheddar cheese. Bake in the preheated oven for 30-40 minutes, or until the peppers are tender and the cheese is melted and bubbly.
Garnish: Remove from oven and let stand for a few minutes. Top with cooked crumbled bacon and chopped parsley or green onions.