Combine 1/4 c bbq sauce with black beans and spread on a foil lined baking sheet. Cook at 350 for about 15 minutes or until the black beans appear cracked.
In a skillet, heat up 2 tsbp olive oil and cook diced mushrooms, diced onion and diced garlic for several minutes.
Add cooked beans, mushrooms, onions, garlic and 3/4 of the rice to a food processor. Pulse several times (should not be a puree, some texture is good).
Dice sweet potato into cubes and add to hot skillet. Cook covered for ~8 minutes or until soft and lightly browned. Transfer sweet potato to a cutting board and chop into smaller pieces. Add sweet potato to food processed mixture.
Transfer mixture to a mixing bowl and add the rest of the rice, the bbq sauce and the spices. Stir together until well combined.
Divide the mixture into 5 even balls and form into patties with your hands. Place in the fridge for 30 minutes.
Once cooled, heat up olive oil on skillet and cook patties for ~3 minutes on each side (should be lightly browned).
Top each patty with more bbq sauce and place in the oven at 375 for about 15 minutes.
Serve on a bun with the toppings you fancy. Can be stored in the fridge for 3-4 days or in the freezer for a month.