If using green lentils: To a small saucepan, add liquid and rinsed green lentils and heat over medium-high heat. Bring to a low boil, then reduce heat to a simmer and cook covered for about 18-22 minutes, or until tender. Drain off any excess liquid and set aside.

If using red lentils: To a small saucepan, add liquid and bring to a boil over high heat. Once boiling, add rinsed red lentils and bring back to a gentle boil. Reduce heat to a simmer and cook uncovered, stirring occasionally, for 7-10 minutes, or until just tender. Drain well and set aside.

In the meantime, heat a large skillet over medium heat. Once hot, add oil, onion, garlic, and bell pepper. Season with a pinch each salt and pepper and stir to combine. Sauté for 4-5 minutes, stirring frequently, or until the peppers and onions are tender and slightly browned.

Next add tomato sauce, coconut sugar, vegan Worcestershire sauce, chili powder, cumin, and paprika (optional). Stir to combine.

Once the lentils are cooked, add them to the skillet as well, and stir to combine. Continue cooking the mixture over medium-low heat until completely warmed through and thick, stirring occasionally - about 5-10 minutes.

Taste and adjust flavor as needed, adding more chili powder and/or cumin for smokiness, salt for saltiness, coconut sugar for sweetness, or Worcestershire for depth of flavor.

Serve the mixture on toasted buns with sliced onion. Best when fresh, though leftover sloppy joe mixture will keep in the refrigerator up to 4-5 days, or in the freezer for 1 month. Reheat in the microwave, or on the stovetop, adding water or vegetable broth if the mixture has dried out.