Melt some butter in a large skillet over medium heat.
Add the onions and peppers and cook for 2-3 minutes.
Stir in the garlic and cook until fragrant.
Add the flour and cook for 1 minutes, while whisking continuously.
Add the heavy cream and reduce the heat to medium-low when it comes up to a boil.
When the cream is nicely thickened turn off the heat and add the cheddar and cream cheese.
Add the cumin, chili powder, dijon mustard, and then simmer for 3 minutes.
Season with salt and pepper and serve immediately!