Black sesame Singapore cookies (shortbread with cashew and egg yolk glaze)

Toast black sesame seeds in a dry saute pan over medium heat until they pop and smoke; let them pop 10 to 15 seconds and turn off. They are done when the white seed showing through split coats has browned.

Grind the toasted sesame to a powder, pulsing and shaking so it does not turn to sesame butter.

Whisk together all-purpose flour, tapioca starch, a little salt and the ground sesame.

In a stand mixer on lowest speed, beat softened unsalted butter briefly to break it up without whisking in air; add icing sugar and neutral oil and mix until combined, scraping once.

Add the dry ingredients in two halves and mix until homogeneous and crumbly, with no lumps of butter or dry flour.

Press the mixture together into a ball; if it cracks everywhere, return it to the mixer and add oil a teaspoon at a time.

Flatten to a sheet about 1 cm thick, starting by hitting it with the rolling pin, then roll to smooth the surface.

Cut with small roundish cutters, avoiding thin corners that burn and break; cut the last of the dough into squares.

Split each cashew in half by removing the small button and rocking a paring knife wedged into the middle.

Brush the cookies with egg yolk, press on a cashew half, and brush once more over the cashews.

Bake until the bottoms are light golden.

Variation: the same recipe with toasted white sesame instead of black.