Preheat oven to 375 degrees. Spray a baking sheet with nonstick spray.
Lay tortillas on the sheet, and spray with nonstick spray. Bake for 5 minutes.
Flip tortillas, and bake until crispy, 3 to 4 minutes.
Meanwhile, bring a skillet sprayed with nonstick spray to medium-high heat. Add beef, mushrooms, and seasonings. Cook, stir, and crumble until beef is fully cooked and mushrooms have softened, 3 to 4 minutes. Add cheese wedge, breaking it into pieces. Cook and stir until cheese has melted and is evenly distributed, about 1 minute.
Divide beef mixture between baked tortillas, and sprinkle with shredded cheese. Top with tomato, onion, pickle, ketchup and mustard.
Makes 1 serving.
350 calories,10g fat, 654mg sodium, 30g carbs, 3g fiber, 7g sugars, 32g protein