Dice the onion, about 1/4 inch dice.
Dice the bell pepper, about 1/4 inch dice.
Mince the garlic, add to the diced onion and bell pepper.
Set aside.
In a large frying pan, melt the butter and add the ground beef. Saute just until cooked through.
Remove all but 2 TB of the fat. You will need some of the fat to saute the vegetables.
Add the onion mixture. Stir and saute until the onions are translucent and the green peppers are softened. They will just be losing their bright green color, about 5 minutes.
Measure the next 7 ingredients. Set aside.
Add the ketchup, spices and 1 cup water. I measured the water in the same measuring cup to rinse out the excess ketchup. Stir well.
Bring to a boil, then turn the burner down to just above a simmer.
Simmer about 15 minutes, stirring regularly until most the liquid has evaporated. Watch that the sugar in the sauce does not burn.
Taste. Adjust flavors - add any salt and pepper needed.
When all the liquid has evaporated, it is ready.
Serve on the buns or rolls of your choice.
Garnish with cheese or avocado, if desired.