Pea tarragon prawn and almond cakes

Name: Pea, tarragon, prawn and almond cakes
Ingredients: 11/2 cup (180g) frozen peas; 1 clove garlic, peeled; 250 gram peeled uncooked medium king prawns (shrimp), chopped coarsely; 1 tablespoon fresh tarragon leaves, chopped coarsely; 1/2 teaspoon finely grated lemon rind; 1 tablespoon ground almonds; 2 cup (235g) firmly packed trimmed watercress; 1 medium fennel bulb (300g), sliced thinly; 1 stalk celery (150g), trimmed, sliced thinly on the diagonal; 1/2 cup (40g) roasted whole blanched almonds, chopped coarsely; 1 tablespoon fresh tarragon leaves, extra; 2 tablespoon olive oil; 1 1/2 tablespoon dijon mustard; 1 tablespoon lemon juice; 1 tablespoon olive oil