Preheat oven to 350°F/177℃ with the rack in the middle.
Line a baking sheet pan with parchment paper. Then place bacon overlapping on the parchment paper. Set aside.
Combine ketchup, Dijon mustard, and sugar in a small bowl, and set it aside.
Pour about a tablespoon of oil into a small-medium saucepan, heat on medium heat.
Add onions, garlic, thyme, and bell pepper. Saute for a minute or two to let the flavors bloom, being careful not to let it burn. Allow it to cool.
Place the ground beef, breadcrumbs, egg, black pepper, Worcestershire sauce, beef bouillon powder, milk, and cayenne pepper (if using any) into a medium bowl. Add the cooled onion mixture. Mix gently until everything is thoroughly combined. DO NOT OVERMIX.
Form the meatloaf like a log on waxed or parchment paper, then transfer it to a prepared sheet pan lined with bacon. Glaze with about ⅔ of the ketchup mix.
Working along the shorter end of the pan, lift the edge of the meatloaf by the parchment underneath and gently fold it inward until it turns over itself. Brush with the remaining ketchup mixture.
Bake for 45-60 minutes or until an instant-read thermometer inserted into the center of the meatloaf registers 160℉/72℃. Let stand 10 minutes before slicing.
Serve with mashed potatoes or desired side dish. Enjoy!