Mushroom burgers with smoky aubergine sauce

“Even the most fanatical meat lovers will love this veggie burger because it has all the classic trimmings of a regular burger, including the chips. The mushrooms replace the buns so it’s also gluten-free but it’s so delicious you don’t feel like you’re missing out on anything. Plus, the aubergine (eggplant) sauce adds that smoky barbecue touch.” Rachel Khoo, Rachel Khoo's Kitchen Notebook Melbourne

• serves

  4

• prep

  30 minutes

• cook

  35 minutes

• difficulty

  Easy

Ingredients

• 2 large sweet potatoes (about 700 g), peeled and cut into 1 cm batons
• 60 ml (¼ cup) olive oil
• 8 vine ripened tomatoes, halved
• 1 tbsp balsamic glaze (available from supermarkets)
• 8 large Portobello mushrooms (about the size of burger buns)
• 225 g haloumi, cut into 4 slices
• 1 tbsp za'artar
• 1 large ox-heart (beefsteak) tomato, sliced
• 1 small red onion, thinly sliced into rounds
• 8 small lettuce leaves
• 1 tbsp sesame seeds

Smoky aubergine sauce

• 1 medium-large aubergine (eggplant)
• 1 bulb of garlic
• 100 g Greek yoghurt
• 1 tsp za'atar
• 1 tbsp pomegranate molasses
• 1 tbsp lemon juice
• 1-2 tbsp extra virgin olive oil
• sea salt and freshly ground black pepper, to taste

Instructions

Preheat a charcoal barbecue to high. When the embers are white, you are ready to cook. 

To make the smoky aubergine sauce, place the aubergine directly in the white embers. Wrap the head of garlic in foil and place in the embers and cook, turning regularly for 20-25 minutes or until the aubergine is charred all over and the garlic is soft to the touch. Remove from the barbecue and set aside to cool. Carefully remove and discard the charred aubergine skin, then place the flesh in a sieve over a bowl and press out as much excess liquid as you can. Squeeze out 4 cloves of roast garlic and add to the aubergine with the remaining ingredients. Combine well, then refrigerate until ready to serve. 

Meanwhile, place the sweet potato batons in a large bowl, drizzle with olive oil and season to taste, then toss to coat well. Brush the tomato halves with oil and season to taste, then place on a wire rack or on the barbecue grill with the sweet potato, making sure they are not crowded. Brush the tomatoes with the balsamic glaze, then close the barbecue lid and cook for 20 minutes, turning regularly or until golden and tender. All barbecues vary in so it’s best to keep an eye on them. When the sweet potato chips are done, you can move them to the side of the barbecue to keep warm while you cook the mushrooms, or place them in a low oven.

When your tomatoes look dark and delicious, remove from the barbecue and leave to cool slightly, then pull away and discard the skins. Place the peeled, roasted tomatoes in a jug, then use a stick blender to process until coarsely chopped. Season to taste and add an extra splash of balsamic glaze and a pinch of sugar if desired. Set aside.

Drizzle the portobello mushrooms with olive oil and season to taste, then cook on the barbecue for 5 minutes on each side or until just tender. In the last few minutes of cooking, drizzle the haloumi with olive oil, then sprinkle all over with the za’tar and cook for 1-2 minutes on each side or until golden.

To assemble, place half the cooked mushroom cup-side up on a serving plate. Top with sliced tomato, lettuce and haloumi, then drizzle with smoky aubergine sauce and a spoonful of the tomato sauce. Top with the remaining mushrooms, sprinkle with sesame seeds and serve with sweet potato chips. 

Recipes from Rachel Khoo’s Kitchen Notebook by Rachel Khoo (Michael Joseph, $39.99). Drop by Rachel Khoo’s website.

Cook's Notes

Oven temperatures are for conventional; if using fan-forced (convection), reduce the temperature by 20˚C. | We use Australian tablespoons and cups: 1 teaspoon equals 5 ml; 1 tablespoon equals 20 ml; 1 cup equals 250 ml. | All herbs are fresh (unless specified) and cups are lightly packed. | All vegetables are medium size and peeled, unless specified. | All eggs are 55-60 g, unless specified.