In a large bowl, beat butter with a mixer at low speed until smooth, approximately 1 minute. Add ⅓ cup confectioners’ sugar, beating until combined, stopping to scrape sides of bowl. Add egg yolk, beating until incorporated. Add lemon zest and vanilla bean paste, beating until combined.
In a medium bowl, whisk together all-purpose flour, almond flour, salt, and remaining 3 tablespoons confectioners’ sugar. With mixer at low speed, add flour mixture to butter mixture in two portions, beating just until combined after each addition. Shape dough into a disk, and wrap in plastic wrap. Refrigerate for 1 hour.
Spray 14 (2½×¾-inch) tartlet pans with cooking spray.
Divide dough into 14 portions. Transfer dough to prepared pans, gently pressing into bottoms and up sides until smooth and even. Using wide end of a chopstick, gently press dough into indentations in sides of pans. Trim excess dough. Place tartlet pans on prepared baking sheet. Freeze for 30 minutes.
Preheat oven to 325°.
Using a fork, prick bottom of each tartlet shell 4 times. Top each tartlet shell with a sheet of parchment paper, letting ends extend over edges of pans. Add pie weights.
Bake for 12 minutes. Carefully remove parchment and weights. Bake until tartlet shells are light golden brown around the edges, approximately 8 minutes more. Let cool completely on a wire rack.
Remove tartlet shells from pans. Fill each shell three-fourths full with chilled Elderflower Pastry Cream. Top with blueberries, blackberries, raspberries, and kiwi.
In a small saucepan, heat jam and 2 tablespoons water over medium-low heat until fluid. Using a pastry brush, brush warm jam onto fruit. Refrigerate until serving time.
Recipe by TeaTime Magazine at https://teatimemagazine.com/elderflower-fruit-tartlets/