In a large pot, melt the butter over medium heat.
Add the onion, bell pepper, jalapeño, and a pinch of salt and cook, stirring, until soft, about 7-10 minutes.
Stir in the flour and continue cooking for another minute.
Add the milk and cook, stirring, until the mixture is thick and coats the back of a spoon.
Add the cheese, stirring until melted, and then add ⅔ cup yogurt, the cayenne, crushed red pepper, a few turns of pepper, and ¼ teaspoon salt.
Taste and adjust seasonings as desired.
To make the cilantro cream, mix the cilantro with the remaining ⅓ cup yogurt and a pinch of salt and a few turns of pepper.
Serve the queso warm with the cilantro cream dolloped in the center.
Top with additional fresh cilantro, chopped bell pepper, black pepper, and a sprinkle of cayenne.
