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  • Megan

roasted portobello mushrooms with basil pesto, mozzarella, and balsamic glaze

Updated: Jul 4

roasted portobello mushrooms stuffed with basil pesto and mozzarella and topped with roasted walnuts and balsamic glaze

I struggle to categorize these. They’re too light to be a meal, but far too decadent to be called an appetizer. Think of this as a small plate you’d order at a nice restaurant. It’s an exceptional treat—something you make for a small group of people you really care about.


3 or 4 portobello mushrooms

3 tablespoons butter

1 large clove garlic, smashed

3 sage leaves

mozzarella pearls (about 36)

1/4 cup balsamic vinegar


1 generous handful fresh basil

heaping 1/4 cup chopped walnuts

1 clove garlic

1/4 cup grated parmesan

1 teaspoon lemon juice

2 tablespoons olive oil

salt & pepper


1. Heat oven to 400°F. Pull the stems out of the mushroom caps. Clean the caps with a damp paper towel.

2. Over medium heat, melt the butter with the smashed garlic clove and sage leaves.

3. Once the butter is fragrant and before it browns, take it off the heat and brush it over the tops of the mushroom caps. Turn over the mushrooms so the gills face up and distribute the butter, garlic, and sage over them. Season with salt.

4. Roast the mushroom caps on a parchment-lined baking sheet for 15 minutes.

5. Meanwhile, heat the walnuts on a skillet over medium heat, shaking or stirring frequently, until the nuts have turned a light golden color; be careful not to burn them. Set aside 1 tablespoon of the nuts for garnish.

6. Toss the basil, remaining toasted walnuts, garlic, grated parmesan, lemon juice, and olive oil into a food processor. Season with salt and pepper. Process until smooth. (Since this isn't a large batch of pesto, my processor struggles to achieve a really smooth pesto—my solution is to transfer the rough pesto to a coffee grinder to finish the job.)

7. When the mushrooms are roasted, brush the accumulated butter and juices around the entire cap. Then fill the caps with the pesto and top with the mozzarella pearls. Put them back into the oven and broil them for a few minutes until the mozz is melted and starting to turn golden.

8. Heat the balsamic vinegar in a skillet or saucepan over medium heat, gently swirling the liquid around the pan as it bubbles. Once the liquid has reduced by at least half and has a syrupy consistency, drizzle it over the finished mushroom caps.

9. Sprinkle the reserved toasted walnuts over the caps and serve.


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