In a high-walled saucepan over medium heat, brown the butter, whisking occasionally. The butter will foam, then the milk solids will sink and turn golden brown. When the butter smells nutty, remove from heat.

Transfer the browned butter to a heatproof container and refrigerate until mostly re-solidified, similar to the texture of room-temperature butter.

While the butter cools, crush the cornflakes in a food processor or sealed bag until finely crushed but not powdery.

In the bowl of a stand mixer or large mixing bowl, add the browned butter. Sift in the powdered sugar and kosher salt. Cream until light and fluffy, scraping down the bowl as needed.

Add ⅓ cup of the crushed cornflakes and the flour. Mix on low until the dough comes together in large clumps.

Transfer the dough onto parchment paper, shape into a rectangle, cover with another sheet of parchment, and roll to 1 cm thickness. Refrigerate for 30 minutes.

Preheat the oven to 325°F. Cut the dough into circles using a cookie cutter (about 7 cm wide).

Place cookies on a parchment-lined baking sheet, spacing 1 inch apart. Chill again for 10 minutes.

Bake for 10–12 minutes, until set and lightly golden on the bottom. Cool completely on a wire rack.

Melt the chocolate using a double boiler. Combine the remaining crushed cornflakes and flaky salt in a small bowl.

Dip half of each cookie into the melted chocolate, shake off excess, then roll the chocolate edge in the cornflake mixture.

Return cookies to the rack and let the chocolate set completely before serving or storing.