Wash your vegetables and thinly slice jalapenos, bell peppers, mushrooms and onion.
Add 1 tablespoon of oil to a medium pan and set on medium heat. Once hot, add garlic and sautee for up to a minute, until just turning golden.
Add mushrooms, onions, pepper and jalapenos and cook covered until mushrooms release some liquid. This should take about 5 minutes.
Add flour and vegetable stock or broth. Continue to cook for another 3 - 5 minutes or until the juice thickens into almost a stew-like consistency. Taste and season accordingly.
While cooking, toast your buns or rolls and have them ready along with your cheese, which should be cut thin enough to melt on the toppings.
Remove your filling from the heat and serve in buns.