You can add onion or other veggies, but keep in mind they'd add moisture, so your breakfast potatoes won't be quite as crisp. For this air fryer breakfast potatoes recipe, you can add up to 1.5 cups of diced onion and/or bell peppers for every 1.5 lb of russet potatoes. (Choose Russet if adding veggies, since they are less starchy). Bake the seasoned potatoes on their own (without veggies) for 10 minutes, then shake the basket and add the lightly oiled veggies. Bake for another 10 to 15 minutes until potatoes are cooked through.