Make the tart crust. First, bring the butter to room temperature (or soften in the microwave at a low setting). Cream until glossy.

Gently mix in the powdered sugar a little at a time. Keep stirring until it the mixture becomes white.

Mix in the vanilla and egg yolk. Add the powdered sugar and use a spatula to cut the dry ingredients into the dough. Press the dough together and wrap with plastic. Chill in the refrigerator for 30 minutes to an hour. (If possible, chill overnight to prevent shrinkage).

Take out of the refrigerator and unwrap. Sandwich the dough between two sheets of wrap and roll it out to about a 2mm thickness. Lightly coat the tart pan with softened butter (or oil) and dust with flour. Line the pan with the dough. Poke holes in the bottom with a fork and chill in the refrigerator.

Make the custard cream. In a heatproof bowl (like the one pictured), mix together the egg yolk and sugar until white. Add the flour and mix. Heat the milk in the microwave and mix in a little at a time. Finally, mix in the vanilla oil.

Microwave for 3 minutes, taking it out to mix with a whisk halfway. It's okay if it forms a skin.

Transfer to a shallow container (or bowl) and press the mixture into the container with plastic wrap. Cool the bottom of the container by placing it in ice water. Transfer to the refrigerator and chill.

Make the almond cream. Put the egg white into a bowl and mix until slightly stiffened. Add the sugar, almond powder, and sifted flour, mixing well. Melt the butter and mix it evenly into the cream.

Cover the bowl with plastic wrap and chill in the refrigerator or freezer until it has thickened to a paste-like consistency. Scoop into the tart crust and smooth it out.

Bake at 170-180°C for 35 minutes. Once baked, transfer to a wire rack and cool. Knead the mixture from Step 7 until creamy and spread over the surface of the tart.

Decorate with various berries and chervil, coat with nappage, and dust the outer edge with powdered sugar to finish.