PREP VEGGIES: Grate onion on large holes of a box grater to get a packed ½ cup; dice bell pepper.
COOK VEGGIES: In a large skillet, melt 1½ tbsp butter over medium-high heat. Add onion, bell pepper, and 2 tsp garlic. Sauté until tender and liquid has evaporated (~5-7 mins).
BROWN BEEF: Push veggies to edge of pan; add beef to center. Let sear and then crumble while incorporating veggies. When mostly browned through, add in tomato paste, bouillon, pepper, mustard powder, and a pinch of salt. Drain excess grease if needed.
SIMMER: Add crushed tomatoes, ketchup, Worcestershire, and brown sugar. Bring to a simmer then reduce heat to low and simmer until thick (10-15 mins). Stir occasionally. Remove from heat. Taste and adjust seasonings.
BREAD PREP: Mix remaining 3½ tbsp butter with remaining 2 tsp garlic and ¼ tsp salt. Cut French bread in half lengthwise. Then cut both halves in half widthwise to get 4 large pieces.
BAKE BREAD: Brush a little bit of the butter on the bottom of all pieces. Place upside down on a foil-lined sheet pan. Bake for 5 minutes. Remove and flip over. Brush rest of butter on inside of bread. Bake for 5 minutes. Remove and let stand then gently press in the centers to make room for meat sauce.
ASSEMBLE: Divide beef mixture evenly between bread. Top with cheese. Bake 10 mins or until cheese melts.
ENJOY: Slice and enjoy immediately garnished with parsley if desired.
Video
Notes
Note 1: Sugar: Adjust brown sugar to taste based on the acidity of the tomatoes used. You might skip it or add a bit more. Taste and adjust accordingly.