In a food processor, combine flour and sugar. Add butter and pulse until it resembles coarse crumbs. Incorporate egg yolk and ice water until a dough forms. Wrap in plastic and chill for at least 1 hour.

Lightly flour your work surface and roll out the dough to 1/8-inch thick. Cut into bunny shape and chill for 15 minutes. Preheat oven to 350°F and bake for 15-20 minutes until golden. Cool on rack.

Heat whole milk and vanilla extract over medium heat until nearly boiling. Whisk egg yolks, sugar, and cornstarch until smooth. Gradually add hot milk while whisking. Return to saucepan and cook until thickened, about 5-7 minutes. Chill.

Whip heavy cream with powdered sugar and vanilla until stiff peaks form. Keep chilled.

Pipe or spread pastry cream into cooled tart shell. Decorate with whipped cream, fresh berries, edible flowers, and chocolate sprinkles.