In a large saucepan over low heat, melt butter. Add onion; sauté 10 to 15 minutes, or until the onions are translucent but not browned. Add the garlic and cook 30 seconds or until fragrant. Add the tomato paste, vinegar, honey, Worcestershire sauce, mustard, soy sauce, hoisin sauce, chili powder, cumin and crushed red pepper flakes. Simmer uncovered on low heat for 30 minutes. Remove from heat and pour into wire strainer to remove onions, garlic and crushed red pepper flakes. Let cool. Store covered in refrigerator. Yield: 1 1/2 quarts.
Trim chicken breasts and thighs of all fat.
Add chicken and 1 cup of barbecue sauce to Instant Pot. Secure lid and make sure that pressure valve is closed. Program on high pressure for 20 minutes. After 20 minutes, quick release pressure. (See Tip 4)
Remove chicken from Instant Pot. Discard liquid.
Shred the chicken using two forks. Transfer to large saucepan. Add 2 cups of barbecue sauce. Stir to combine. Cook over low heat 15 minutes or until chicken is moist with barbecue sauce and is thoroughly heated.
Serve heaped onto slider buns with additional barbecue sauce on the side.
Yield: 12 servings.