Oven Baked Portobello Mushroom Burgers with Truffle Sauce

Two portobello mushroom burgers sitting on baking paper.

Oven Baked Portobello Mushroom Burgers with Truffle Sauce

Rich and savory, French-inspired mushroom burgers with a creamy truffle sauce.

Course Main Course

Cuisine Western

Keyword burger, mushroom, truffle

Prep Time 5

Cook Time 25

Marinade 20

Total Time 50

Servings serves

Calories 316kcal

Author Lauren

Ingredients

Balsamic Marinated Mushrooms

4 large portobello mushroom, slightly larger than the burger buns (Note 3)
3 tbsp balsamic vinegar
3 tsp worcestershire sauce (Note 4)
3 tsp nutritional yeast
2 garlic cloves, minced
2 tsp extra virgin olive oil
1/2 tsp dijon mustard (Note 4)
1/4 tsp dried thyme, optional
1 1/2 tbsp water

Truffle Yoghurt Sauce

2/3 cup greek yoghurt, low/reduced fat
1/2 tsp dijon mustard (Note 4)
1 1/2 tsp white wine vinegar
2 tsp truffle infused extra virgin olive oil (Note 5)
1/8 tsp white pepper

Other Burger Ingredients

1 medium onion, thinly sliced
1 tsp extra virgin olive oil, for the onions
4 burger buns, preferably wholemeal/wholegrain/whole wheat
2-3 medium tomatoes, sliced
4 cups rocket / arugula
4 slices swiss cheese, low/reduced fat

Cups - Metric

Instructions

Balsamic Marinated Mushrooms

Add the balsamic vinegar, Worcestershire sauce, nutritional yeast, Dijon mustard, minced garlic, extra virgin olive oil and water into a small bowl. Mix the ingredients together with either a whisk or a fork until the Dijon mustard and nutritional yeast have mostly dissolved into the liquid.
Arrange the portobello mushrooms in a large tray, gill side down. Don’t worry if they overlap a bit. Give the balsamic marinade a quick stir and pour it over the mushrooms. Using a spoon, scoop up the marinade in the tray and pour it over any missed parts of the mushrooms. Set aside for 10 minutes if time permits. You can reduce the marinade time to 5 minutes per side or skip it completely if needed.
Turn the mushrooms over, scoop the balsamic marinade with a spoon and drizzle it allover the underside of the mushrooms. Try to pick up most of the minced garlic, as they will become lodged in the gills and give the mushrooms more flavour. Set aside for another 10 minutes if time permits.

Baking the Mushrooms

Preheat oven to 200°C/390°F.
Line a large baking tray with baking paper. Place the mushrooms on the tray, gill side up and then bake in the oven for 20 minutes or until the centres of the mushrooms are tender when pierced with a toothpick. Reserve the leftover marinade in the tray. We will be using that for the caramelised onions. (While the mushrooms are in the oven, make the yoghurt truffle sauce and cook the onions).
Remove the tray from the oven, and flip the mushrooms over using a pair of tongs so the gills are facing down. Place a piece of Swiss cheese over the top of each mushroom. Put the tray back in the oven for 2-3 minutes or until the cheese has melted over the mushrooms.

Caramelised Onions

Heat the extra virgin olive oil in a small frypan over high heat. Add the thinly sliced onions and cook, stirring occasionally, for 5 minutes or until they have almost completely wilted.
Pour the reserved balsamic marinade into the frying pan and stir to coat the onions. Important: Do not stand over the frying pan when cooking the balsamic marinade, as inhaling the fumes makes it difficult to breathe! Make sure you have your range hood/fume extractor on or have a window open nearby. Continue to cook the onions for another 5 minutes, stirring occasionally, or until the balsamic marinade completely evaporates and the onions are soft and caramelised. Remove the frypan from the heat and set aside.

Yoghurt Truffle Sauce

Add all the sauce ingredients to a bowl and stir well to mix. Cover the bowl with plastic wrap and place the truffle sauce in the fridge until ready to assemble the burgers.

Assembling the Portobello Mushroom Burgers

Lightly toast the cut sides of the burger buns (optional).
Spread the yoghurt truffle sauce over the base of the bun. Top with rocket / arugula, sliced tomato, then the baked portobello mushroom. Top the mushroom burgers with the balsamic caramelised onions and the lid of the bun. Serve the mushroom burgers immediately while hot with your favourite burger sides.

Notes

Health benefits - Details regarding the benefits of portobello mushrooms and other ingredients in this recipe are in the post above.
Other cooking methods & instructions with photos - Detailed in the post above.
Portobello mushrooms - Can be substituted for thinly sliced swiss brown/cremini mushrooms. Marinade the mushrooms for 20 minutes and saute them in a skillet until soft. Create 4 individual piles on a baking tray/in a large frying pan, top the mounds with the Swiss cheese, and cook until the cheese has melted. Carefully transfer to the burger buns using an egg flipper.
Worcestershire sauce & dijon mustard - Can be very high in excess sodium. Where possible, choose a mustard and sauce that has“no added/reduced salt”, or has the lowest sodium per 100g.
Truffle infused extra virgin olive oil - Can be substituted for truffle paste, start with 1/2 a tsp and add more to taste. Can also be left out if it does not fit within your budget.
Big eaters/meat lovers - You can add a meat patty (beef mince/steak, ground chicken or chicken breast/thigh) to your mushroom burgers. Otherwise, you can use vegetarian patties or add an additional portobello mushroom.
Gluten free - Swap the burger buns for a certified gluten-free variety to make these Mushroom Burgers gluten-free. Also, check to ensure that your Dijon mustard and Worcestershire sauce are certified gluten-free, as they may have hidden gluten-containing ingredients.
Diabetes friendly - Change the burger buns for a low GI or lower carb alternative. Otherwise, you could use lettuce leaves instead of the burger buns or have the mushroom burger deconstructed.
Vegan - Swap the Swiss cheese, Greek yoghurt and burger buns for plant-based versions. You could also use lettuce leaves in place of the burger buns and have the mushroom burger deconstructed.
Storage - The portobello mushrooms with/without the Swiss cheese will keep in an airtight container in the fridge for up to 3 days. To reheat, place the mushrooms in a microwave-safe container and heat them on high for 1 minute or until hot, or reheat in the oven until warm to the touch. To freeze, separate the cooked mushrooms with plastic sheets/parchment paper and place them into a freezer-safe container or bag.
Nutrition - Calculated per serve, assuming 4 serves of mushroom burgers with no sides.

Nutrition