Prep: 1. Heat grill (medium-high heat). 2. Brush mushrooms on both sides with oil; sprinkle with salt and pepper. Make: 1. Grill mushrooms, rounded side up, 4 minutes. Turn over, cover and grill until tender, about 4 minutes. 2. Mix pesto and mayonnaise. 3. Serve mushrooms topped with red peppers, arugula, and cheese.
Check out our favorite tips for grilling here - http://blog.gatheredtable.com/2015/06/26/barbecue-basics/ These are great on grilled buns! When the mushrooms are just about done cooking grill the buns, cut side down, for about 2 minutes or until they begin to brown.