Wash and dry all produce. Place a baking sheet on upper rack of oven. (TIP: Use two sheets if you you can’t fit the flatbreads on one.) Preheat oven to 450 degrees. Pat chicken dry with a paper towel and slice into thin strips. Season all over with salt and pepper.

Melt 2 TBSP butter in a large pan over medium-high heat (use a nonstick pan if you have one). Add chicken and cook about 2 minutes. Add barbecue spice and 3/4 tsp chili powder (save the rest for the crema). Toss to coat and continue cooking until chicken is lightly browned, about 2 minutes more.

Stir 2 tsp sugar and 1 cup water into pan. Simmer until thickened slightly, about 2 minutes more. Add 4 TBSP butter, stirring to melt. (TIP: Cut it into smaller pieces first to help it melt faster.) Transfer chicken and its sauce to a medium bowl and let cool slightly.

Meanwhile, halve and slice tomatoes. Halve, peel, and thinly slice shallots. Halve and thinly slice jalapeños, removing ribs and seeds first for less heat. Spoon chicken and its sauce over flatbreads in an even layer. Top with tomatoes, shallost, and half the sliced jalapeño (use more if you’d like some extra heat).

Carefully remove baking sheet(s) from oven (use your mitts). Transfer pizzas to sheet(s) and sprinkle evenly with cheese. Bake until flatbreads are golden brown and crisp, 8-10 minutes. Meanwhile, in a small bowl, mix together a pinch of chili powder, sour cream, and 2 TBSP water. Season with salt, pepper, and more chili powder, to taste.

Transfer baked pizzas to a cutting board and cut into squares. Dollop with crema and serve.