Caprese stuffed portobello mushrooms are filled with melty mozzarella, juicy grape tomatoes and basil pesto, then finished with balsamic. An easy, Mediterranean-inspired vegetarian dinner or side!
Preheat the oven to 375°F (190°C). Line a rimmed baking sheet with parchment paper.
Wipe the mushroom caps clean with a damp paper towel. Gently twist off the stems, then scrape out the dark gills with a spoon and discard them.
Using a pastry brush, brush the olive oil over the outside of each cap and around the inside and edges. Set the caps gill side up on the lined baking sheet.
Divide the mozzarella evenly among the caps. Top each one with the halved grape tomatoes and dot or drizzle with the pesto. Sprinkle with salt and pepper to taste.
Bake on the middle rack for 15 to 20 minutes, until the mushrooms are fork-tender and the cheese is melted and bubbly.
Drizzle with aged balsamic vinegar or balsamic glaze, if desired, and serve right away.
Notes
Fresh mozzarella releases more liquid than shredded low-moisture mozzarella. Pat it dry before using, and lift the baked mushrooms off the pan with a spatula to leave any juices behind.For bite-size appetizers, use cremini (baby bella) mushrooms and bake for 10 to 12 minutes.Leftovers keep in an airtight container in the refrigerator for up to 3 days. These don't freeze well.