Mustard and lemon dressing
1.Boil, steam or microwave peas and garlic together until peas are tender; drain.
2.Blend or process garlic and 1 cup of the peas with prawns, chopped tarragon, rind and ground almonds until combined; season. Using oiled hands, roll level tablespoons of prawn mixture into 16 balls; flatten slightly. Cover; refrigerate for 1 hour. (The patties are quite sticky, however they will not fall apart during cooking).
3.Meanwhile, make mustard and lemon dressing. Whisk ingredients in a small bowl until combined; season to taste.
4.Place watercress, fennel, celery, blanched almonds, extra tarragon and remaining peas in a large bowl with half the dressing; toss to combine.
5.Heat oil in a large non-stick frying pan over medium heat; cook patties, in batches, for 2 minutes each side or until golden and cooked through. Cover to keep warm.
6.Serve patties with salad, drizzled with remaining dressing.
Patties can be made up to 1 day ahead; store in an airtight container in the fridge. Use a mandoline or V-slicer to slice the fennel very thinly.Note