How to Make It
Heat oil in a large nonstick skillet over medium-high heat. Sprinkle mushrooms with salt and pepper. Add mushrooms to pan; sauté 4 minutes or until tender, turning once. Add garlic to pan; sauté 30 seconds. Remove from heat.
Combine cheese and mayonnaise, stirring well. Spread about 2 tablespoons mayonnaise mixture over bottom half of each roll; top each serving with 1/2 cup arugula and 2 tablespoons peppers. Place 1 mushroom on each serving, and top with top halves of rolls.
Portobello mushrooms are well-paired with pungent Gorgonzola cheese. Use crumbled blue cheese to save even more time.