Beat softened butter and granulated sugar together in a large mixing bowl for 2 to 3 minutes until fluffy.

Add egg yolks one at a time, mixing well after each addition, then add vanilla extract.

Mix in flour and salt gradually until just combined.

Wrap the dough in plastic and chill in refrigerator for at least 30 minutes.

Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.

Scoop and roll dough into smooth balls (about 24).

Dip each ball in egg whites, then roll in shredded coconut.

Press a deep indent into the center of each ball for jam.

Fill each indent with half a teaspoon of jam carefully to avoid overflow.

Bake for 14-16 minutes, watching for golden coconut.

Let cool on the baking sheet for 5 minutes before transferring to a wire rack.