01 - Cream together butter and powdered sugar in a large bowl until smooth and fluffy. Beat in vanilla extract until fully incorporated.
02 - Sift flour and salt into the butter mixture. Mix until just combined and a dough forms, being careful not to overwork.
03 - Divide dough in half and shape into 2-inch diameter logs. Wrap tightly in plastic wrap and refrigerate for at least 30 minutes.
04 - Preheat oven to 350°F and line baking sheets with parchment paper.
05 - Slice chilled dough into 1/2-inch thick rounds and place on prepared baking sheets. Bake for 12–14 minutes until edges are lightly golden. Cool completely on wire racks.
06 - Whisk together egg yolks, 1/4 cup granulated sugar, heavy cream, and vanilla in a small saucepan. Cook over medium-low heat, stirring constantly, until mixture thickens slightly, about 4–5 minutes. Remove from heat and cool completely.
07 - Spoon a small amount of cooled custard onto the center of each cookie. Smooth gently with the back of a spoon or offset spatula.
08 - Sprinkle a thin, even layer of granulated sugar over the custard on each cookie. Use a kitchen torch to caramelize the sugar until golden and crisp. Let set for 5 minutes before serving.