Cream butter and powdered sugar together until smooth.

Add egg yolk and mix thoroughly.

Sift flour and coconut flour into the mixture and combine using a spatula.

Wrap the dough in plastic wrap, flatten slightly, and refrigerate for at least 30 minutes.

Prepare the Coconut Roche mixture by combining egg white, sugar, and lemon preserve. Mix lightly.

Add shredded coconut and coconut flour to the mixture and stir until combined.

For the Coconut Cream, cream butter and powdered sugar together until smooth.

Gradually add beaten egg in 2–3 portions, mixing well after each addition.

Mix in lemon preserve and sifted dry ingredients, stirring until smooth.

Add heavy cream and yogurt powder, mixing until fully incorporated.

Roll out the chilled tart dough to 3–5mm thickness and line a tart pan. Prick the base with a fork.

Fill the tart shell with Coconut Cream mixture.