Spring-Fresh Rhubarb Raspberry Tart with Vanilla Quark Mousse

Mix flour, cold butter cubes, powdered sugar and salt in a bowl. Rub with hands to form crumbs. Add egg and quickly knead to a smooth dough. Form into a ball, wrap in plastic wrap and chill for 30 minutes.

Butter a 28cm tart pan. Roll out dough on floured surface to 3mm thickness and place in pan. Press edges and trim excess dough. Prick several times with a fork. Chill for 30 minutes.

Preheat oven to 180°C (350°F). Place parchment paper on dough, weigh down with baking beans. Bake for 15 minutes, then remove weights and paper. Bake another 10 minutes until golden brown. Cool completely.

Simmer rhubarb, raspberries, sugar and lemon juice in a pot over medium heat for 8-10 minutes. Mix cornstarch with 3 tbsp cold water and stir into fruit mixture. Cook 2 minutes more until thickened. Cool completely.

Soak gelatin sheets in cold water for 5 minutes. Heat 3 tbsp water, dissolve squeezed gelatin in it. Cool slightly but don't let it set.

Split vanilla pod lengthwise, scrape out seeds. Mix quark, powdered sugar and vanilla seeds until smooth. Whip cream to stiff peaks. Stir gelatin solution into quark, then gently fold in whipped cream. Use immediately.

Spread fruit filling evenly over baked base. Fill quark mousse into piping bag with star tip and pipe decoratively over fruit. Alternatively, spread with spoon and smooth surface.

Chill tart for at least 3 hours until set. Before serving, decorate with fresh berries and mint leaves. Cut into portions with a sharp, damp knife.