How to make delicious vegetarian hamburgers
For the cheese and onion cutlets:
Cook the potatoes in a large saucepan of salted, boiling water until tender to the tip of a knife, about 15-20 minutes.
In the meantime, heat the olive oil in a frying pan set over a medium heat.
Add the onion and a pinch of salt, sweating until translucent but uncoloured, about 5-6 minutes. Set aside to cool.
When ready, drain the potatoes and tip back into the bowl they were cooked in.
Mash well, adding the onion, cheddar, cornflour, and some salt and pepper to taste.
Divide into four and shape into puck-sized cutlets between floured palms.
Dust the patties in flour, shaking off the excess. Dip in the beaten egg to coat and then roll in the breadcrumbs, coating all over.
Place on a tray, cover, and chill until ready to fry.
For the fried beetroot:
Heat the olive oil in a frying pan set over a medium heat.
Add the sliced beetroot and a pinch of salt, sautéing until starting to crisp at the edges.
Remove from the heat and stir in the feta and season to taste with salt and pepper.
For the avocado salad:
Stir together all the ingredients for the avocado salad in a small mixing bowl. Season to taste with salt and pepper.
Heat the vegetable oil in a large, heavy-based saucepan to 180°C | 345F.
Deep-fry the cutlets until golden-brown and crisp, turning over in the oil a few times, about 5 minutes.
Remove from the oil and drain on kitchen paper, covering loosely with aluminium foil to keep warm.
Stir together the garlic, mayonnaise, plain yogurt, and 1 tbsp hot water in a small mixing bowl. Season with a little salt and pepper.
Spread onto the cut sides of the buns.
Top two burger bun bottoms with some rocket and then the cutlets and avocado salad.
Top with more rocket and then tops of the buns.
Top the remaining burger bun bottoms with cutlets and then the fried beetroot.
Sit the tops of the buns in place before serving.