Melt the butter in a medium-size pot over medium heat. Add the chopped onion and saute for 3-4 minutes until translucent. Add the minced garlic and cook for 2 more minutes until fragrant.

Add the canned tomatoes and the salt, black pepper, cumin, and cayenne, and stir. Cook while occasionally stirring for 5 minutes.

Add the cream cheese and heavy cream and stir until the cream cheese has melted. Add the grated cheddar cheese and stir until fully incorporated. Cook for a few minutes until a smooth sauce forms.

Take the mixture off the heat and add the chopped cilantro, if desired. Season with more salt, pepper, or cayenne if you wish. Serve with keto-friendly dippers like raw vegetables or keto crackers, pork rinds, or drizzle on meat dishes.