For the salad: Wash the cucumber and cut into wide ribbons with the coarse use of the spiral cutter.
Peel the beetroot and cut into spaghetti with the fine insert.
Wash the lettuce leaves.
Cut the onion into fine rings.
Halve the avocado, remove the stone, remove the pulp and cut into strips.
Spread the lettuce leaves on a deep plate and cover with the cucumber strips.
Pour most of the beetroot spaghetti on top.
Place the avocado strips on top, spread the remaining beetroot on top.
Garnish with crumbled goat cheese and onion.
For the dressing: squeeze the lemon, peel the garlic clove and chop finely.
Mix lemon juice, egg yolk, oil and garlic with a blender.
Season to taste with salt and pepper.
Before serving, pour the dressing over the salad.