In a medium sized skillet, heat butter and oil over medium heat. When butter is melted, add onions and cook for 3-4 minutes or until translucent. Add peppers and garlic and cook, stirring, for 2 minutes or until fragrant.
Add flour, chili powder, and cumin, and cook for 2-3 minutes while stirring constantly.
Slowly add milk while stirring constantly. Add chili powder and cumin. Cook for 4-5 minutes, stirring frequently, until thickened.
Reduce heat to low and stir in cheddar and cream cheese until melted. Stir in cilantro.
Serve warm with chips.
It’s best to buy a block of cheese and grate it yourself for the smoothest queso.
Queso will solidify slightly as it cools. Keep warm over low heat on the stovetop or in a slow cooker set on the “warm” setting. To reheat, slowly warm over low heat on the stovetop while stirring frequently.