In a skillet, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Add the minced garlic and cumin, and cook for another minute until fragrant.

Stir in the cooked beans and vegetable broth. Mash the beans with a potato masher until desired consistency is reached.

Cook for about 10-15 minutes, stirring occasionally, until heated through and thickened. Season with salt to taste.

Serve warm, topped with cheddar cheese if desired.