Place ½ cup whole grain elbow pasta, a couple pinches of salt, and ½ cup water in a 16-oz. mug; place mug in a microwave-safe bowl to catch any spillover. Microwave on high until pasta is tender, 6 minutes, stopping to stir every 1 minute. If water boils over, add 2 Tbsp. more, to keep pasta moist. Drain any excess water. In a separate mug, microwave 2 oz. crumbled ground beef and ½ cup chopped mushrooms on high until meat is cooked through, 3 minutes. Stir in ½ cup marinara sauce and ½ tsp. each dried oregano, garlic powder, and onion powder. Microwave until warmed through, 30 seconds. Add meat sauce to mug with pasta and garnish with Parmesan.