In a large pot, heat the olive oil over medium heat. Add the diced onion and minced garlic. Stir occasionally for about 5-7 minutes until the onion turns translucent.

Increase the heat to medium-high. Add ground beef to the pot. You want to break it apart with a spoon and cook until browned. This should take about 10 minutes. Make sure it’s cooked through for food safety.

Now, sprinkle in the chili powder, smoked paprika, Italian seasoning, ground cumin, and red pepper flakes. Stir for a minute or two to toast the spices slightly, which unlocks their flavors.

Introduce the canned crushed tomatoes and drained kidney beans to the pot. Give everything a good stir. This is where the magic starts to happen!

Add dark brown sugar and mix it well into the chili. It helps to balance the acidity of the tomatoes. Then, sprinkle your all-purpose flour and stir again. It will start to thicken beautifully.

Pour in the white vinegar, add Worcestershire sauce if using, and season with salt and pepper. Lower the heat, cover the pot, and allow the chili to simmer for at least 30 minutes. This is crucial; it enhances the flavor by melding all those ingredients.