Lentil Burgers with Beetroot Rolls and Vegan Mayonnaise

• 200 g lentils
• water, for soaking

Mayonnaise

• 250 g groundnut oil
• 50 g olive oil
• 15 g lemon juice
• 100 g soya milk
• 1 garlic clove
• 1 tsp fine sea salt

Bread

• 150 g sweet potatoes, cut in pieces (2 cm)
• 400 g water
• 100 g cooked beetroot, cut in pieces
• 25 g fresh yeast, crumbled
  ou 2 tsp dried instant yeast
• 500 g bread flour, plus extra for dusting
• 1 tsp fine sea salt

Burgers

• 1000 g water
• 1 ½ tsp fine sea salt
• 70 g bread, torn in pieces
• 10 g fresh parsley, leaves only
• 100 g red onions, quartered
• 50 g wheat germ
• 25 g olive oil, plus extra for frying
• fresh spinach leaves, to serve