Preheat the oven to 200°C. 

Bring a medium pan of water to the boil. Cut each asparagus spear into three short lengths. Drop the asparagus onto the pan and let it boil for 3 minutes, lift out with a draining spoon and lower into a bowl of iced water. 

Roll the pastry out to a rectangle measuring 38cm by 25cm. Cut out six discs of pastry approximately 12cm in diameter. Place the discs on a lined baking sheet. Using the tip of a knife, score a smaller circle 1cm in from the edges of each piece of pastry. Brush a little beaten egg around the outside of each piece of pastry. 

Drain the asparagus on kitchen paper. Crush the cheeselets with a fork and fold in the fresh cream, thyme and half the Parmesan. Divide the mixture between the six discs of pastry and put four asparagus pieces on each. Scatter over the remaining Parmesan.

Put the baking sheet in the oven and bake for 25-30 minutes, until the tarts are golden. Eat immediately.