Spread goat's cheese on the halves of the mini burger buns. Place baby spinach, circle of a beetroot, micro greens, sliced avocado, marinated onions on top of the burger bun. Finish the burger with the second half.
The marinated onions you make as follows: slice red onions, put them in hot water for about 5 minutes, make a marinade with 50 ml of water and 25 ml of apple vinegar, a tea spoon of sugar, a tea spoon of salt, black pepper and bay leave. Press the onions tight into a glass jar, fill it with the marinade, close and let it stay for 24 hours in a fridge.