Preheat oven to 300 degrees. Season chicken thighs with salt and pepper.

Heat 1 tbsp butter in a heavy ovenproof skillet over medium-high heat. Place half the chicken thighs top side down into the pan. Brown on one side, then remove to a plate and repeat until all chicken is browned.

Melt the remaining tbsp of butter in skillet. Add onions to pan. Cook until translucent, about 5-7 minutes. Deglaze with Bourbon, scraping the bottom of the pan, and allowing Bourbon to reduce for a minute or two. Add garlic and cook 1 minute. Pour in barbecue sauce, peach preserves, water, and Worcestershire sauce. Stir until combined, then return chicken to the skillet top side up and place in oven.

Bake for 25-30 minutes, or until an internal temperature of 165 degrees is reached.

Remove skillet from oven and return to stove top. Remove chicken from BBQ sauce, set aside on the place. Turn heat on low to bring BBQ sauce to simmer. In small mixing bowl combine 1 tbsp of cornstarch and 1 tbsp of water. Add to BBQ sauce and whisk to incorporate. This will thicken the sauce.

Remove from heat and return chicken to thickened BBQ sauce. Serve warm.