1. Sauté Aromatics:
- In a large saucepan or Dutch oven, melt the tablespoon of butter over medium heat.
- Add the chopped onion and diced celery to the melted butter. Sauté, stirring occasionally, until the vegetables are tender, about 5-7 minutes.
- Add the minced garlic and cook for another minute until fragrant, stirring constantly to prevent burning.
2. Build the Barbecue Sauce:
- Stir the salsa, ketchup, packed brown sugar, cider vinegar, Worcestershire sauce, chili powder, salt, and pepper into the saucepan with the sautéed vegetables.
- Mix well to combine all the sauce ingredients.
3. Add Chicken and Simmer:
- Add the 2 cups of shredded cooked chicken to the sauce in the saucepan.
- Stir everything together until the chicken is well coated with the barbecue sauce.
- Bring the mixture to a gentle boil.
- Once boiling, reduce the heat to low, cover the saucepan with a lid, and let it simmer for 15 minutes. This allows the chicken to absorb the sauce and the flavors to meld beautifully. Stir occasionally.
4. Prepare Buns and Serve:
- While the chicken mixture simmers (or just before serving), split your hamburger buns and toast them to your liking (in a toaster, under a broiler, or cut-side down in a dry skillet).
- To serve, spoon about 1/3 cup (or desired amount) of the hot barbecue chicken mixture onto the bottom half of each toasted bun.
- Top with dill pickle slices, if using, and then place the top half of the bun.
- Serve the Barbecue Chicken Sandwiches immediately while warm. Enjoy!