Step 1

In a bowl, add the Worcestershire sauce, the mustard, the brown sugar, and the tomato sauce and whisk to combine.

Step 2

Set the sauce mixture aside.

Step 3

In a large skillet or a Dutch oven over medium-high heat, add the olive oil and the ground beef and cook, while crumbling, until the meat is just starting to brown, about 4-5 minutes.

Step 4

Season the beef with 1/2 teaspoon of the salt and 1/4 teaspoon of the black pepper.

Step 5

Add the diced green peppers and the onion to the beef and cook, while stirring, until the vegetables are tender, about 5 minutes

Step 6

Add the minced garlic to the beef mixture and cook, while stirring frequently, until fragrant, about 30 seconds.

Step 7

Add the sauce mixture to the beef mixture and bring it to a light boil.

Step 8

Reduce the heat to low.

Step 9

Simmer the mixture, uncovered, until it reaches your desired thickness, about 10-15 minutes.

Step 10

Season the mixture as needed with the extra salt and the extra pepper.

Step 11

If the sauce is too thin, gradually add the water, until it reaches your desired consistency. You may not need all or any of the water.

Step 12

Serve the sauce with the buns.