Beat in the lemon zest and the egg. Scrape the edges of the bowl and continue to mix.

Sift the flour with the baking powder and add to the mixture. Beat on low speed until completely combined.

Scoop the dough and roll balls with your hands. Place them separately on a tray lined with parchment paper. Press each cookie lightly with the palms of your hands. Make a small hole in the center with your finger or the tip of a small rolling pin or wooden spoon.

For the filling, cut the quince paste into cubes and place them in a saucepan with 2 tablespoons of water. Bring to low heat and mash with a fork until forming a softer paste, like a thick jam.

Fill the cookies with the quince paste.

Bake in a preheated oven at 180 ° C for 10-12 minutes, or until the bases of the cookies are just golden brown. Let cool before serving.