Soak the gelatin sheet in cold water until soft.

In a small saucepan, heat the blackcurrant purée with sugar until just simmering.

Squeeze out the gelatin, stir into the hot purée until fully dissolved.

Pour into the small ring cavities of your mold; freeze solid.

Preheat the oven to 170 °C (thick ovens or fan).

Whisk together ground almonds, sugar (I), and yolks until thick and pale.

Dissolve matcha powder in a tablespoon of hot water; blend into the yolk mixture at low speed.

In a clean bowl, beat egg whites and sugar (II) to stiff peaks.

Fold a little meringue into the yolk mixture, then gently fold in the remaining meringue along with sifted flour.

Spread the batter thinly (about 5 mm) on a parchment-lined sheet or silicone mat.

Bake for 15 minutes; allow to cool completely.

Use the smaller side of your ring cutter to punch out matcha sponge rings that fit inside your tart molds.

Warm the coconut purée in a saucepan.

In a bowl, whisk the yolks with sugar. Soak gelatin in cold water.

Pour hot coconut purée over the yolk mixture, return to the saucepan, and heat—stirring constantly—until the mixture reaches about 83 °C.

Remove from heat; stir in the drained gelatin until dissolved.

Pour the hot custard over the chopped white chocolate; let sit 1 minute, then stir until smooth.

Cool, stirring occasionally, to about 30 °C.

Whip the cream to soft peaks and fold gently into the custard.

Cream butter and sugar together, then mix in the egg yolk, vanilla powder, and citrus zests.

Stir in the flour until a homogeneous dough forms.

Chill the dough for at least 1 hour.

Roll between parchment to about 3 mm thickness; cut rings with the larger side of your cutter.

Bake on a lined tray at 170 °C until golden (about 12–15 minutes). Cool completely.

Bloom gelatin in the portion II water.

In a saucepan, combine glucose syrup, sugar, and portion I water; heat to 103 °C.

Off heat, stir in sweetened condensed milk and the bloomed gelatin.

Place chopped white chocolate in a tall bowl; pour the hot mixture over it. Add moss-green gel coloring.

Emulsify with an immersion blender—keep the blade submerged to avoid air.

Cover the glaze’s surface with cling film; refrigerate overnight.

Remove the frozen blackcurrant inserts from the mold.

Pipe or spoon coconut mousse into the larger ring cavities up to midway.

Gently press one blackcurrant insert into each, then pipe more mousse to fill to the top.

Place a matcha sponge ring on each and freeze the tarts solid (preferably overnight).

On service day, warm the mirror glaze to about 35 °C.

Unmold the frozen tarts and place them on a wire rack set over a tray.

Pour the glaze evenly over each tart, then let excess drip off.

Wipe the bottom edge clean, transfer to shortbread rings, and allow to thaw briefly in the fridge.