Lemon Curd Filled Madeleines

Place all ingredients for the lemon curd in a microwave safe bowl and microwave on medium for approximatley 4-5 mins, until curd thickens. Check and stir regularly to ensure egg doesn't scramble. Set aside to cool.
Preheat oven to 350F/180C. Melt butter and leave to cool to room temp. Meanwhile beat eggs and slowly add sugar mixed with the lemon zest until it has the consistency of thick mayonnaise.
In another bowl, mix together flour, baking powder and salt. Slowly sprinkle this on top of the egg mixture and fold in with a wooden spoon or spatula. Once folded in, slowly drizzle in the cooled butter and the vanilla extract and mix until incorporated.
Cover bowl and place in fridge of about 1 hour then take out of fridge and leave for about 1/2 hour before spooning into a greased madeleine pan. Fill each mould about 3/4 full as the mixture will expand in the oven. Cook in oven for around 7-9 mins. Check at around 5 mins to see how they are going as cooking times will vary with ovens.
Once cooked, take the madeleienes out of the oven and turn out onto a wire rack. Place the cooled lemon curd into a piping back with a small nozzle and while the madeleines are still warm, pipe the lemon curd into the madelience by poking a hole on the underside of the madeleine towards the side and fill till it starts coming out.
Dust with icing/confectioner's sugar and serve immediately while still warm.