This is a hearty sandwich that is full of rich flavors and textures. Makes 2 sandwiches.
Mix mayonnaise and chili powder together and let chill for a couple of minutes before using. Store in refrigerator for later use.
Remove stem from mushroom, scrape out the gills and wipe down with a damp cloth or paper towel. Brush both sides with olive oil and salt and pepper. Broil mushroom 3”-4” from heat for about 4 minutes on each side. They can also be grilled or seared in a skillet. Remove mushroom when browned and slice into ½” strips. Split toasted baguettes down the center, lengthwise. Spread on spicy mayonnaise on both baguette halves. On one half, layer mushrooms, sliced tomatoes, lettuce, onion slices and added salt and pepper. Close sandwich with other half and serve.
Mix together and chill for 10 minutes before serving. Store leftovers in refrigerator.