Rinse the vegetables. Peel the asparagus and cut off the ends. Cut into 5 cm long pieces (approximately 1 1/2 inches). Rinse and trim the snow peas and cut off the ends.
Bring 1 liter of water (approximately 4 cups) to a boil and season with salt and lemon juice. Cook the lower sections of the asparagus for about 8 minutes and then add the asparagus tips and the snow peas. Continue cooking for another 7 minutes and then drain. Set aside about 1/2 cup of the asparagus stock.
Rinse the tomatoes and cut into eighths. Rinse the salad burnet, shake dry, remove any coarse stems and chop.
For the dressing, press the egg yolks through a sieve and mix with the mustard and asparagus stock. Season with salt and pepper and then mix in 4 tablespoons of oil with a whisk. Add half of the salad burnet and season to taste.
Mix the dressing with the tomatoes, snow peas and asparagus and transfer to glasses, bowls or plates.
Break the crispbread into small pieces. Heat the remaining oil and toast until crispy and browned. Shower over the salad.
Garnish with the remaining salad burnet and serve immediately.