Vegan Burger with Mango Salsa and Caramelized Onions

First, prepare the dill dressing. Put both types of mustard, white wine vinegar, agave syrup (or cane sugar), and 5 sprigs of finely chopped dill into a blender and blend briefly. Slowly add 2 tbsp olive oil and continue blending until a smooth emulsion forms. Season with a pinch of salt and pepper and let it chill in the refrigerator.

Heat 2 tbsp olive oil in a pot and add the red onions cut into rings. Sauté covered over medium heat for about 15 minutes, stirring occasionally. When the onions are soft and golden brown, stir in cane sugar and balsamic vinegar. Season with salt and pepper and simmer uncovered for another 5 minutes until the liquid has thickened to a syrup-like consistency.

For the salsa, finely purée half of the peeled mango with a pinch of salt, pepper, and lime juice. Cut the remaining mango into small cubes and fold into the purée.