1) In a small bowl combine the chicken, ricotta cheese, lemon zest, thyme, salt, and pepper. Stir to combine.
2) On a dry work surface place eight wonton wrappers. Place a rounded teaspoon of the chicken mixture in the centre of each wrapper. Using a pastry brush, brush the egg wash around the chicken mixture. Bring four corners of the wonton square together over the filling to form a purse. Press the edges together tightly to form a seal. Wipe the board with a towel until dry and continue making batches of eight with the remaining wonton skins
3) Meanwhile, bring a large pot of salted water to a boil over high heat. Add the purses and cook until they float to the surface, stirring occasionally, about 4 to 5 minutes. Drain.
4) Melt 60g of butter in a medium frying pan. Turn off the heat, add the cooked purses and gently toss. Transfer the purses to four serving plates. Sprinkle with grated Parmesan and sprinkle with salt and pepper.
5) Serve immediately.