In a large skillet over medium heat, add the ground beef. Cook until browned, about 5-7 minutes, using a wooden spoon to break up the meat as it cooks.
Drain excess fat if necessary, then add the diced onions and green bell pepper to the skillet. Sauté for another 3-4 minutes until the vegetables are soft.
Stir in the minced garlic and cook for an additional minute until fragrant.
Add the ketchup, Worcestershire sauce, brown sugar, mustard, salt, and pepper to the skillet. Mix well and let it simmer on low heat for about 10 minutes, stirring occasionally.
While the filling is simmering, preheat your broiler. Spread softened butter on one side of each slice of Texas toast.
Place the Texas toast, buttered side up, on a baking sheet and broil for 2-3 minutes until golden and crispy.
Once the filling is ready, spoon it generously onto the unbuttered sides of the Texas toast slices. Top with optional garnishes if desired.
Serve immediately with remaining Texas toast on the side.