Mince garlic and finely chop bell pepper and onion.
Heat up butter in a skillet over medium heat. Add beef mince and cook until brown. Remove from heat and set aside.
Add garlic, onion and bell pepper to the same skillet and cook for a few minutes until fragrant.
Add the rest of the ingredients (apart from the buns) to skillet and stir well until combined. Cook for 10-15 minutes until it thickens to desired consistency.
Meanwhile, toast your buns.
Remove meat sauce from heat, and serve immediately over toasted buns.
Notes
Adjust amount of ketchup according to your preference.
Adjust cooking time according to your preference. If you want a thicker sauce, cook it for longer. If you want a thinner sauce, add more water.
Use whatever buns you like to suit your dietary requirements.
The meat sauce can be made ahead of time and stored in the fridge for 3 days or freezer for 3 months.