Place parsnips in a baking paper lined baking dish, sprinkle leek over the top and liberally spray with oil. Season to taste. Bake in a preheated oven at 220ºC for 20 minutes, turning half way through cooking. Remove from oven and reduce temperature to 170ºC.
Whisk eggs, cream and milk together in a large jug. Stir in thyme and season to taste.
Lightly spray 24 x 1/3 cup capacity muffin pans with oil. Line each mould with a prosciutto slice, easing in to cover base and sides.
Divide Edgell Butter Beans into each muffin pan. Top with roasted vegetables. Pour in egg mixture allowing a quarter of a cup for each one. Lightly sprinkle with parmesan.
Bake for 25 minutes or until set and lightly golden. Cool for 15 minutes in pans before carefully removing to cool completely. Serve garnished with extra thyme.