Add avocado oil to your Instant Pot and select the “Sauté” setting.
Chop onion, bell pepper, and garlic and add to the heated Instant Pot.
Sauté until soft, 3-5 minutes, stirring frequently.
Add the vegetable broth, lentils, and salt to the Instant Pot.
Prepare your Instant Pot for pressure cooking — cover and lock the lid, making sure the venting knob is in the Sealing position.
Using the “Pressure” button, set the Instant Pot to pressure cook on HIGH pressure for 15 minutes. Depending on the model of Instant Pot you are using, this button may be called something else — like “Manual” or “Pressure Cook”.
Once the timer goes off, allow the pressure cooker to naturally release pressure — this will take about 10 minutes. Once complete, turn the venting knob to the Venting position to release any remaining pressure before removing the lid.
Turn the Instant Pot to “Sauté” once more and add the remaining ingredients except for the buns — tomato sauce, Lucky Foods Bulgogi Sauce, maple syrup, apple cider vinegar, paprika, and red chili flakes if using. Taste and adjust if needed. Adding these ingredients now allows you to adjust to your flavor preferences — add more tomato sauce if you wish, maple syrup for extra sweetness, Bulgogi Sauce for more BBQ flavor, apple cider vinegar if you need to balance out sweetness, or red chili flakes for more heat. Stir frequently until heated thoroughly and the desired thickness is achieved.
Spoon the mixture onto buns and serve with toppings of your choice. I used a slaw made from shredded broccoli stems, carrots, and thinly sliced apple — mixed with yogurt, mustard, lemon juice, apple cider vinegar, salt, and pepper.