Creamy vegetable soup, steamed chicken with vegetable tagliatelle and mustard sauce

Soup, steamed chicken and vegetable tagliatelle

• 80 - 100 g onions, cut in halves
• 1 garlic clove
• 20 g olive oil
• 1 - 2 carrots
• 1 courgette
• 400 g water, plus extra for soup
• 2 tsp salt
• 450 g mixed vegetables (e.g. potato, courgette, carrot, leek), cut in pieces
• 500 g chicken breast fillets, skinless, cut in strips (5 cm x 2 cm)
  of 500 g turkey breast fillets, skinless, cut in strips (5 cm x 2 cm)
• 20 g butter (optioneel)
  of 1 Tbsp cream (optioneel)

Sauce

• 50 g crème fraîche
  of 50 g cream, min. 30% fat
• 1 Tbsp mustard
• ½ tsp salt
• 1 pinch ground black pepper
• 3 - 4 sprigs fresh parsley, leaves only
• 1 egg yolk (optioneel)