Grilled leek and egg salad with mustard and caper dressing

Ingredients

• 4 large eggs
• 3 x 175g packs baby leeks
• 1 tsp vegetable bouillon powder
• 2 tsp olive oil
• ¼ tsp mixed peppercorns, lightly crushed
• a few rocket leaves
• 1 tbsp white wine vinegar
• 1 small shallot, very finely chopped
• 1 garlic clove, crushed
• 1 tbsp drained capers
• 1 tbsp chopped fresh tarragon, plus a few leaves to garnish
• 1 tsp Dijon mustard
• 1 tsp wholegrain mustard
• 2 tbsp extra-virgin olive oil
• sea salt, to taste