In a large pot, cook bacon over medium heat until crispy, about 7 minutes. Remove bacon with a slotted spoon and drain on paper towels.
Pour off excess bacon fat, leaving about 1 to 2 tablespoons in the pot. Add onion, bell pepper, jalapeño, and thyme, cooking until vegetables are soft, about 5 minutes.
Reduce heat to medium, add butter and stir until melted. Sprinkle in flour and cook, stirring, for 1 minute to remove the raw flour taste.
Gradually pour in beer while stirring, then add chicken broth and heavy cream. Stir continuously until the mixture is smooth and begins to thicken.