Roasted Flat Mushrooms with Green Onion, Thyme & Herb Butter Recipe

Introduction

These roasted flat mushrooms with green onion, thyme, and butter make a flavorful and elegant side dish. The combination of fresh herbs and rich butter enhances the meaty texture of portobello mushrooms, perfect for any meal.

Ingredients

• 8 large flat mushrooms (portobello or “BBQ”), about 10–12cm (4–4.5″) wide, stem tips trimmed
• 100g (7 tbsp) unsalted butter, softened
• 1 cup green onion (scallions), thinly sliced
• 1/3 cup parsley, finely chopped
• 1 tbsp fresh thyme leaves (or 1 tsp dried thyme)
• 1/2 tsp salt
• 1/4 tsp black pepper
• 3 tbsp chopped scallions (for garnish)
• 1 dozen thyme stalks (for garnish)

Instructions

1. Step 1: Clean the mushrooms by wiping them gently with a damp cloth or paper towel to remove any dirt. Avoid washing under water to keep mushrooms from becoming soggy.
2. Step 2: Preheat your oven to 200°C (390°F) or 180°C fan.
3. Step 3: In a medium bowl, combine the softened butter with green onion, parsley, fresh thyme leaves, salt, and black pepper to create the herb and green onion butter.
4. Step 4: Place the mushrooms gill side up on a large baking tray. Spread the herb butter evenly over the mushroom surfaces. Cover the tray with foil to help preserve the green color of the herbs.
5. Step 5: Bake in the preheated oven for 25 minutes, or until the mushrooms are tender and cooked through.
6. Step 6: Remove from the oven and arrange the mushrooms on a serving platter, including all the butter and juices from the tray. Scatter with extra chopped scallions and thyme stalks for a fresh, vibrant touch before serving.

Tips & Variations

• For an extra layer of flavor, add a splash of white wine or lemon juice to the butter mixture before spreading on the mushrooms.
• If fresh thyme is unavailable, dried thyme works well—just use about one-third of the fresh amount.
• Try adding a sprinkle of grated Parmesan on top before baking for a cheesy variation.

Storage

Store leftover mushrooms in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at a low temperature to maintain their texture, or warm in a microwave for a shorter time. Avoid overheating to prevent drying out.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I use other types of mushrooms for this recipe?

Yes, while flat portobello mushrooms are ideal for their size and texture, you can also use large cremini or button mushrooms. Adjust baking time slightly if using smaller mushrooms.

Is it possible to make this recipe vegan?

To make a vegan version, substitute the butter with a plant-based margarine or vegan butter. The herbs and onions will still provide plenty of flavor.

Roasted Flat Mushrooms with Green Onion, Thyme & Herb Butter Recipe

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★★★★★

4.8 from 139 reviews

Delicious roasted flat mushrooms generously coated with a flavorful herb and green onion butter, baked to tender perfection. This easy-to-make dish is enhanced with fresh thyme and scallions, making it a perfect savory side or appetizer.

• Author: Clara
• Prep Time: 10 minutes
• Cook Time: 25 minutes
• Total Time: 35 minutes
• Yield: Serves 4
• Category: Side Dish
• Method: Baking
• Cuisine: American
• Diet: Vegetarian

Ingredients

Scale 1x2x3x

Mushrooms

• 8 large flat mushrooms (portobello, about 10–12 cm / 4–4.5 inches wide, stem tips trimmed)

Herb & Green Onion Butter

• 100g (7 tbsp) unsalted butter, softened
• 1 cup green onion (scallions), thinly sliced
• 1/3 cup parsley, finely chopped
• 1 tbsp fresh thyme leaves (or 1 tsp dried thyme)
• 1/2 tsp salt
• 1/4 tsp black pepper

For Garnish

• 3 tbsp chopped scallions
• 1 dozen thyme stalks

Instructions

1. Clean mushrooms: Trim stem tips of the flat mushrooms and wipe them clean gently with a damp cloth or paper towel to remove any dirt without soaking them.
2. Preheat oven: Set your oven to 200°C (390°F) or 180°C fan-forced to prepare for roasting the mushrooms.
3. Mix butter: In a medium bowl, combine the softened unsalted butter with thinly sliced green onions, chopped parsley, fresh thyme leaves, salt, and black pepper. Stir thoroughly until the herb butter is evenly mixed.
4. Smear mushrooms: Arrange the mushrooms on a large baking tray with the gills facing upward. Spread the herb and green onion butter evenly over each mushroom’s surface, ensuring good coverage. Cover the tray with aluminum foil to help preserve the bright green color of the herbs during roasting.
5. Bake mushrooms: Place the covered tray in the preheated oven and roast for approximately 25 minutes, or until the mushrooms become tender and juicy.
6. Serve: Transfer the mushrooms onto a serving platter, including all the melted butter and juices from the baking tray. Garnish by scattering extra chopped scallions and fresh thyme stalks over the mushrooms for a fresh, aromatic finish, then serve immediately.

Notes

• Note 1: When cleaning mushrooms, avoid rinsing them under water as they can absorb moisture; instead, use a soft brush or damp cloth.
• Using fresh thyme enhances aroma, but dried thyme can be substituted if fresh is unavailable.
• Covering the mushrooms with foil while baking helps maintain herb color and moisture.
• Serve warm as a side dish or appetizer to complement grilled or roasted meats.

Keywords: roasted mushrooms, portobello mushrooms, herb butter, green onion, thyme, vegetarian side dish, baked mushrooms