Oven-Roasted Portobello Mushrooms with Garlic Herb Butter

By , Test Kitchen Director · Reviewed by AislePrompt Editorial · ·

Juicy portobello mushrooms roasted in the oven and topped with a rich garlic herb butter for a savory vegetarian side dish. This mediterranean-inspired vegetarian (vegetarian) ready in about 30 minutes pairs caps large portobello mushrooms, unsalted butter, minced garlic cloves for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 150 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 10 min Cook: 20 min Serves 4 Mediterranean cuisine 150 cal/serving
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Ingredients

Instructions

  1. Step 1: Preheat your oven to 400°F. Remove the stems from 4 large portobello mushrooms and gently wipe the caps clean with a damp paper towel. Place them gill-side up on a baking sheet lined with parchment.
  2. Step 2: In a small bowl, combine 4 tablespoons unsalted butter, 3 minced garlic cloves, 2 tablespoons finely chopped fresh parsley, and 1 tablespoon fresh thyme leaves. Mix well until evenly blended.
  3. Step 3: Drizzle 2 tablespoons olive oil evenly over the mushroom caps, then sprinkle 1 teaspoon salt and 1/2 teaspoon black pepper over them. Spread the garlic herb butter mixture evenly inside each mushroom cap.
  4. Step 4: Roast the mushrooms in the preheated oven for 20 minutes until they are tender and the butter has melted into the meaty caps, releasing a fragrant garlic herb aroma. Serve warm.

Equipment for this recipe

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Frequently asked questions

How long does Oven-Roasted Portobello Mushrooms with Garlic Herb Butter take to make?

Total time is about 30 minutes (10 min prep + 20 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Oven-Roasted Portobello Mushrooms with Garlic Herb Butter?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep unsalted butter from drying out.

Can I substitute ingredients in Oven-Roasted Portobello Mushrooms with Garlic Herb Butter?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Oven-Roasted Portobello Mushrooms with Garlic Herb Butter for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

Is Oven-Roasted Portobello Mushrooms with Garlic Herb Butter vegetarian?

Yes — this recipe is tagged vegetarian based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.

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