Caramelized Onions & Mushrooms On Toast is a comforting, savoury recipe that transforms simple ingredients into a delicious meal worthy of a cosy weekend brunch or an easy weeknight dinner.
Slices of toasted sourdough are topped with buttery mushrooms, sweet caramelized onions, garlic, fresh thyme and a rich cream sauce finished with melted Gruyère cheese. Every bite delivers a satisfying combination of crisp bread, tender vegetables and creamy, cheesy goodness.
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What Is Mushrooms on Toast?
Mushrooms on Toast is a classic savoury dish featuring cooked mushrooms spooned over slices of toasted bread. Popular in British cooking and café menus, it can be as simple as mushrooms sautéed in butter and garlic or as indulgent as a creamy mushroom sauce served over thick slices of rustic bread.
Our recipe takes the traditional dish a step further by combining sliced button mushrooms with slowly caramelized sweet onions. The vegetables are cooked with garlic, honey and sherry, then simmered in table cream with Dijon mustard, Worcestershire sauce and fresh thyme. Shredded Gruyère is stirred into the sauce just before serving, creating a rich, velvety topping.
The finished mushroom mixture is spooned generously over toasted sourdough bread. The bread provides a crisp, sturdy base that contrasts beautifully with the creamy topping, making this an excellent option for anyone who loves hearty vegetarian meals and classic comfort food flavours.
Why You’ll Love Mushrooms on Toast
- Rich, savoury flavour: Garlic, Worcestershire sauce, Dijon mustard and fresh thyme give the creamy mushroom sauce plenty of depth, while the cheese adds a deliciously savoury finish.
- Sweet caramelized onions: Slowly cooking the onions brings out their natural sweetness, complementing the earthy mushrooms and balancing the richness of the cream.
- A comforting meatless meal: Mushrooms provide a satisfying, substantial topping, making this recipe a wonderful option for a vegetarian lunch or dinner. Check that your Worcestershire sauce is vegetarian if needed.
- Easy one-pan cooking: The mushroom and onion mixture comes together in a single skillet, keeping cleanup simple.
- Perfect for sourdough lovers: Toasted sourdough adds a tangy flavour and crisp texture that stands up well to the creamy topping.
- Easy to customize: Choose Gruyère for a nutty, classic French-inspired flavour or aged cheddar for a sharper, more pronounced cheese taste.
- Versatile enough for any meal: Serve it for brunch, a light lunch, a casual dinner or as a savoury starter for a relaxed dinner party.
Recipe Tips
- Take your time caramelizing the onions. The onions are an important source of sweetness and flavour in this recipe. Cook them over medium-low heat, stirring regularly, until they’re soft and golden. If they begin to brown too quickly, lower the heat and add a small splash of water.
- Give the mushrooms room to brown. Mushrooms release a considerable amount of moisture as they cook. Avoid overcrowding the pan, and allow the liquid to evaporate before expecting the mushrooms to develop a golden-brown exterior. If your skillet is small, cook the mushrooms in batches.
- Choose the right mushrooms. Button mushrooms are affordable, easy to find and ideal for this recipe. Cremini mushrooms offer a slightly deeper, earthier flavour, while a mixture of cremini, shiitake and oyster mushrooms can make the dish feel more restaurant-worthy.
- Use freshly shredded cheese. Freshly grated Gruyère or aged cheddar generally melts more smoothly than pre-shredded cheese, which often contains anti-caking agents. Gruyère provides a nutty, buttery flavour, while aged cheddar adds a sharper finish.
- Simmer gently after adding the cream. Keep the sauce at a low simmer rather than allowing it to boil rapidly. Gentle heat helps the cream reduce without making the sauce greasy or causing it to separate.
- Toast the bread thoroughly. The creamy topping is delicious but can quickly soften bread. Toast the sourdough until crisp and assemble each serving immediately before eating. Thick-cut slices are especially good because they provide a sturdy base.
- Adjust the sauce consistency. If the sauce seems too thin, simmer it uncovered for a few extra minutes to reduce the liquid. If it becomes too thick, stir in a small splash of cream or water until it reaches your preferred consistency.
- Make it your own. Add a pinch of chilli flakes for heat, a little freshly grated nutmeg for warmth, or a handful of chopped parsley for freshness. You can also finish the dish with a few drops of sherry vinegar or lemon juice to brighten the creamy sauce.
Serving Suggestions
Onions & Mushrooms On Toast is substantial enough to enjoy on its own, but it’s also easy to build into a more complete meal. Because the topping is rich and creamy, fresh vegetables, crisp salads and tangy accompaniments work particularly well.
- Serve with a green salad: Toss rocket, baby spinach or mixed greens with a simple lemon vinaigrette. The fresh, acidic dressing cuts through the richness of the cheese and cream.
- Pair with roasted vegetables: Roasted asparagus, broccolini or green beans make excellent seasonal side dishes. Their fresh, slightly bitter flavours balance the savoury mushroom sauce.
- Enjoy for brunch: Serve alongside softly scrambled eggs, poached eggs or a simple omelette for a hearty weekend brunch.
- Turn it into an appetizer: Use smaller slices of toasted baguette or sourdough to make individual mushroom toasts for a dinner party. Spoon the topping onto the bread just before serving.
- Serve with soup: Pair a smaller portion with a light vegetable soup or a simple broth-based soup for a comforting lunch.
- Finish with fresh herbs: A scattering of chopped parsley, chives or thyme adds colour and freshness. A little extra freshly cracked black pepper is also delicious.
For drinks, try a crisp Sauvignon Blanc, a dry cider or sparkling water with lemon. If you’re serving this dish as part of a brunch spread, freshly brewed coffee or a cappuccino is an equally welcome pairing.
Storage Tips
- Refrigerating leftovers: If you have leftover creamy mushroom and onion sauce, allow it to cool slightly before transferring it to an airtight container. Refrigerate within two hours of cooking and use within 3–4 days. Store the topping separately from the toasted bread to prevent it from becoming soggy.
- Reheating the mushroom mixture: Transfer the topping to a skillet and reheat gently over low to medium-low heat, stirring frequently until piping hot throughout. If the sauce has thickened in the refrigerator, add a small splash of cream or water to loosen it. Avoid high heat, which can cause the cream sauce to separate.
- Freezing: Freezing is not recommended for the finished cream-and-cheese sauce because its texture may become grainy or separate when thawed. For the best results, prepare only as much as you plan to eat, or refrigerate any leftover topping for another meal.
- Make-ahead preparation: To save time, caramelize the onions and cook the mushrooms a day in advance. Refrigerate the mixture, then add the cream, mustard, Worcestershire sauce and thyme when you’re ready to finish the dish. Simmer until the sauce thickens, stir in the cheese and serve over freshly toasted sourdough.
- A versatile sauce: My family often likes to repurpose the leftover mushroom sauce by stirring it into a risotto or al dente pasta.
Caramelized Onions & Mushrooms On Toast
Equipment
- French knife
- measuring cups
- measuring spoons
- Non-stick skillet
- Wooden spoon or spatula
- cheese grater
- Toaster
Ingredients
- 2 tbsp Unsalted Butter
- 4 Garlic Cloves minced
- 2 Medium Spanish Onions thinly sliced
- 1 tbsp Honey
- 2 oz Dry Sherry or Sweet Vermouth
- Salt & Pepper
- 400 g Button Mushrooms sliced
- 2 tsp Worcestershire Sauce
- 1 cup Table Cream
- 1 tsp Dijon Mustard
- 1 sprigs Fresh Thyme
- 1 cup Gruyere or Old Cheddar Cheese shredded
- 6 Sourdough Bread Slices
Instructions
- In a large nonstick skillet over medium heat at butter. Once bubbling add garlic and stir, cooking until browned approximately 2 minutes.
- Add sliced onions, honey and sherry. Add salt and pepper to taste. Stir then let sit for 5-10 minutes on medium-low heat to brown and caramelize. Stir the onions every few minutes for another 10 minutes to produce nicely browned and softened onions.
- Add sliced mushrooms, stir and then cover with a lid for 5-7 minutes to help the mushrooms soften. Remove the lid and stir mushroom and onion mixture until nicely browned, another 8-10 minutes.
- Add Worcestershire Sauce, cream, mustard, and thyme. Stir together and let reduce for 10-15 minutes on low heat.
- Meanwhile, toast sourdough bread slices in a toaster or oven.
- Moments before you're ready to serve, add the grated cheese to the mushroom cream mixture and stir until combined, 2 minutes.
- Scoop mushroom cream over sourdough bread slices and serve immediately.
Nutrition
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