Gather the ingredients.
Rinse the beans and pick them over. Look for small stones and discard any malformed beans.
Add the beans to the pot with 8 cups of water and 1 teaspoon of kosher salt.
Lock the lid in place and make sure the valve is in the sealing position. Choose pressure cook/manual, high pressure, and set the timer for 25 minutes. When the time is up, cancel the keep warm button and let the pressure come down naturally for 10 minutes. Move the valve to the venting position to release the remaining pressure. Diana Rattray
Reserve 1 cup of the cooking liquid and drain the beans. Set the beans and reserved liquid aside.
Wipe out the inner pot and choose the sauté button. Add the diced bacon to the pot and cook for about 5 minutes, or until browned.
Add the onion, bell pepper, and garlic to the pot and cook for 2 minutes longer.
Add the brown sugar, molasses, ground mustard, black pepper, red pepper flakes, and the reserved liquid. Stir to blend and scrape up any browned bits stuck on the bottom of the pot.
Add the beans back to the pot and top them with the barbecue sauce (the tomato paste will be added later). Do not stir.
Lock the lid in place and check that the valve is in the sealing position. Choose the pressure cook/manual button, high pressure, and set the timer for 5 minutes. When the time is up, let the pressure come down naturally for 10 minutes and then carefully release the remaining pressure manually.
Stir the tomato paste into the beans.
Serve the beans with cornbread, biscuits, or brown bread and garnish them with sliced green onions, if desired.