Grilled Welsh Rarebit Stuffed Portobello Mushrooms

Introduction

There is something truly magical about transforming a classic British comfort dish into a smoky, outdoor masterpiece. Welsh Rarebit—essentially the world's most sophisticated cheese on toast—relies on a savory, stout-infused cheese sauce that packs a punch of umami. By swapping the traditional bread for meaty, earthy Portobello mushrooms and preparing them on the grill, you elevate this dish from a simple snack to a gourmet main course or a show-stopping appetizer. The high heat of the grill intensifies the natural flavors of the mushrooms, creating a tender, juicy vessel perfect for holding the molten gold cheese sauce. Whether you are a vegetarian looking for a hearty option or a meat-eater seeking a decadent side, this recipe bridges the gap between pub fare and backyard barbecue. The combination of sharp cheddar, dark beer, and the smokiness from the fire creates a flavor profile that is robust, complex, and utterly irresistible.

Ingredients

The Mushrooms

• 4 large Portobello mushrooms, stems removed and gills carefully scraped out
• 3 tablespoons extra virgin olive oil
• 1 teaspoon sea salt
• 1/2 teaspoon freshly cracked black pepper

The Welsh Rarebit Filling

• 2 tablespoons unsalted butter
• 2 tablespoons all-purpose flour
• 1/2 cup dark beer (Stout or Porter works best for depth)
• 1 teaspoon Worcestershire sauce
• 1 teaspoon dry mustard powder
• 1 pinch cayenne pepper (optional for heat)
• 1 1/2 cups sharp Cheddar cheese, freshly grated
• 2 tablespoons heavy cream
• 1 large egg yolk (to bind the sauce)
• Fresh chives, chopped (for garnish)

Instructions

Step 1: Fire Up the Grill

1. Begin by preparing your Arteflame grill or charcoal grill. You want a medium-high heat zone for grilling the mushrooms directly and a slightly cooler zone (or a cast iron skillet placed on the grill) for preparing the cheese sauce without burning it.
2. If using an Arteflame, aim to use the flat cooktop surface which provides excellent heat control. Ensure the surface is seasoned and ready for cooking.

Step 2: Prepare the Mushrooms

1. Clean the Portobello mushrooms with a damp paper towel to remove any dirt. Do not soak them.
2. Remove the stems and use a spoon to gently scrape out the black gills from the underside of the caps; this ensures the sauce doesn't turn a muddy color and creates more room for the filling.
3. Brush the mushroom caps generously with olive oil on both sides and season with salt and pepper.

Step 3: Create the Rarebit Base

1. Place a cast-iron skillet on the grill surface. Melt the butter until it begins to foam.
2. Whisk in the flour and cook for about 2 minutes, stirring constantly to cook out the raw flour taste but without letting it brown too deeply.
3. Gradually pour in the dark beer, whisking vigorously to prevent lumps. The mixture will thicken rapidly into a smooth paste.

Step 4: Finish the Cheese Sauce

1. Lower the heat (move the skillet to a cooler part of the grill). Stir in the heavy cream, Worcestershire sauce, dry mustard, and cayenne pepper.
2. Gradually fold in the shredded cheddar cheese, a handful at a time, stirring until completely melted and smooth.
3. Remove the skillet from the heat entirely. Let it cool for one minute, then quickly whisk in the egg yolk. This enriches the sauce and helps it set slightly when broiled later.

Step 5: Grill and Stuff

1. Place the mushroom caps on the hot grill grates or flat top, gill-side down first. Grill for 3-4 minutes until they develop a nice sear.
2. Flip the mushrooms over so the cup side is facing up. Grill for another 2-3 minutes until they are tender and juices begin to pool.
3. Spoon the warm Rarebit cheese mixture generously into each mushroom cap.

Step 6: The Final Melt

1. Cover the grill with a lid or use a basting dome over the mushrooms to trap the heat. Cook for an additional 2-3 minutes until the cheese sauce is bubbly and slightly golden on top.
2. Remove from the grill, garnish with fresh chopped chives, and serve immediately while hot.

Tips

To achieve the absolute best results with your Grilled Welsh Rarebit Stuffed Mushrooms, temperature control is paramount. The cheese sauce, traditionally known as a roux-based sauce, can separate if it gets too hot after the cheese is added. Always remove the skillet from direct, searing heat when folding in the cheddar to ensure a velvety, smooth texture rather than a greasy one. Regarding the mushrooms, resist the urge to wash them under running water; Portobellos are like sponges and will absorb liquid, making them soggy when grilled. A damp cloth is all you need. Finally, using a high-quality, aged sharp cheddar is non-negotiable here. The sharpness cuts through the richness of the beer and butter, providing that signature punch that defines authentic Welsh Rarebit. If your sauce becomes too thick while waiting for the mushrooms, a splash of warm milk will bring it back to the perfect consistency.

Variations

While the traditional Welsh Rarebit flavor profile is timeless, these stuffed mushrooms are a fantastic canvas for culinary creativity. You can easily adapt the recipe to suit different dietary preferences or flavor cravings without losing the essence of the dish. For those who love a bit of texture, adding a crunch element to the topping before the final melt can add a delightful contrast to the creamy sauce and tender mushroom. Here are a few ways to customize your grill session:

• The Carnivore's Delight: Crumble crispy bacon or pancetta over the top of the cheese sauce just before serving for a salty, smoky crunch.
• The Spicy Kick: Add chopped pickled jalapeños into the cheese sauce and swap half the cheddar for Pepper Jack cheese.
• The French Twist: Use Gruyère cheese instead of Cheddar and use a dry white wine instead of stout beer for a fondue-like flavor profile.
• The Herb Garden: Mix fresh thyme and rosemary into the mushroom marinade and top with crispy fried onions.
• Mini Bites: Use Cremini (Baby Bella) mushrooms instead of Portobellos to create bite-sized appetizers perfect for parties.

Best pairings

These Grilled Welsh Rarebit Stuffed Portobello Mushrooms are robust enough to stand on their own, but they truly shine when paired with complementary flavors. Because the sauce is rich and savory, you want sides and drinks that can cut through the creaminess or echo the earthy notes of the dish. If serving this as a main course, a crisp, acidic salad is essential to cleanse the palate between bites. A simple arugula salad with a lemon vinaigrette works wonders here. For beverages, sticking to the roots of the recipe is a winning strategy. The remaining stout or porter used in the sauce makes for an excellent drinking companion, as does a full-bodied red wine like a Cabernet Sauvignon or a Syrah.

• Grilled Flank Steak: The mushrooms act as a luxurious side dish to lean cuts of beef.
• Arugula and Fennel Salad: The peppery greens and anise flavor cut through the rich cheese.
• Crusty Sourdough Bread: Perfect for mopping up any cheese sauce that escapes the mushroom caps.
• Roasted Asparagus: Grill them alongside the mushrooms for a complete vegetarian meal.

Conclusion

Mastering these Grilled Welsh Rarebit Stuffed Portobello Mushrooms adds a sophisticated yet comforting weapon to your BBQ arsenal. This recipe perfectly encapsulates the joy of outdoor cooking: taking simple, high-quality ingredients and using the fire to coax out their best qualities. The smokiness of the grill adds a dimension that a kitchen oven simply cannot replicate, marrying the earthiness of the fungi with the tangy, malty richness of the British rarebit tradition. Whether you are hosting an elegant backyard dinner party or simply treating yourself to a gourmet weeknight meal, these mushrooms promise a flavor experience that is both nostalgic and excitingly new. Gather your ingredients, light up the grill, and prepare for a dish that will have everyone asking for seconds.