In a big bowl, use a mixer to mix the butter and powdered sugar until it’s fluffy. Add the egg yolks one by one, then add the vanilla and mix everything together.

In another bowl, mix the flour and salt. Pour this into the butter mixture and mix until it’s all combined.

Cover the dough and put it in the fridge for about 30 minutes to make it firm.

Set the oven to 350 F. Put parchment paper on two cookie sheets.

Roll the dough into 1-inch balls, about the size of a big marble. Place them on the cookie sheets. Press your finger in the middle of each ball to make a small dent. Fill the dent with a little bit of pineapple jam. Pinch the edges to cover the jam, then use a fork to make a crisscross design on top. Brush each tart with the beaten egg.

Bake the tarts for 15 to 18 minutes or until they look golden and shiny. Remove and let the tarts cool on a wire rack.