Green-Tea Profiteroles

Craquelin: Beat butter with salt and brown sugar on medium-high speed until light and fluffy, about 2 minutes. Beat in flour and sesame seeds. Roll mixture between 2 sheets of parchment to a scant 1/8 inch thick. Freeze until firm, about 20 minutes.

Pâte à Choux: Preheat oven to 375°F. In a medium saucepan, bring butter, granulated sugar, salt, and 1/2 cup water to a boil. Remove from heat; using a wooden spoon, quickly stir in flour. Return to medium-high heat; cook, stirring constantly, until mixture pulls away from sides and a film forms on bottom of pan, 2 to 3 minutes. Remove from heat; let cool 2 minutes. Vigorously beat in whole eggs, one at a time, until dough is sticky and forms a soft peak when pressed and lifted with a finger. If peak doesn't form, beat remaining egg white and stir in a bit at a time until it does.

Transfer dough to a piping bag fitted with a 1/2-inch round plain tip (such as Ateco #806). Pipe eight 2-inch-diameter mounds onto a parchment-lined baking sheet (for easier piping, adhere corners of parchment to sheet with tiny dollops of dough). Stamp out frozen craquelin using a 2-inch round cutter (if dough cracks, let stand at room temperature 1 minute; if dough becomes too soft, return to freezer for a few minutes). Top choux mounds with craquelin rounds; do not press down.

Bake until profiteroles are puffed, golden brown, and hollow-sounding when tapped on bottoms, about 30 minutes. Turn oven off. Using a wooden skewer or toothpick, poke a hole in the side of each profiterole and leave in oven with door slightly ajar for 15 minutes (this will prevent the puffs from collapsing as they cool). Transfer profiteroles to a wire rack; let cool completely.

Crème Anglaise: Prepare an ice-water bath, if using (see below). In a small saucepan, heat milk over medium-high just until bubbles form around edges and it starts to steam. Remove from heat. In a heatproof bowl, whisk together granulated sugar, ginger, and egg yolks until pale and thick, about 2 minutes. Slowly add hot milk, whisking constantly. Pour mixture back into pan.

Cook over medium-low heat, stirring constantly, until custard is thick enough to coat the back of a spoon and a line holds when swiped with a finger, about 10 minutes. Strain mixture through a fine-mesh sieve into another bowl; stir in vanilla. Let cool over ice-water bath, stirring occasionally; or cover and refrigerate until cold, at least 30 minutes, or up to 5 days in an airtight container.

Spoon a few tablespoons of crème anglaise onto serving bowls. Using a serrated knife, split profiteroles horizontally and place bottoms in bowls. Top each with a scoop of ice cream and pastry tops. Sprinkle with candied ginger and more sesame seeds; serve immediately.