Preheat and prep: Heat oven to 350°F (175°C). Grease and line a 9x13-inch pan (or a sheet pan if you scale up). Sift flour and baking powder together; set aside.

Cream or combine: Beat room-temperature butter and granulated sugar until light. Add eggs one at a time, then fold in lemon zest and vanilla.

Build the batter: Alternate adding dry ingredients and milk/buttermilk, beginning and ending with dry ingredients. Mix until just combined — don’t overbeat.

Pour batter into prepared pan and bake for 25-35 minutes (for the 9x13 size), or until a toothpick inserted near center comes out with a few moist crumbs. Let cool in pan for 10 minutes, then remove to a rack for further cooling.

Whisk confectioners’ sugar with lemon juice and honey until smooth. It should be pourable but not runny.

When the cake is warm but not hot, pour the glaze and spread it evenly. This helps it adhere.

In a heavy saucepan, combine granulated sugar, a splash of water, and corn syrup. Heat without stirring until it reaches about 300–310°F (hard crack) or becomes a deep amber.

Remove from heat and quickly whisk in sifted baking soda — it will foam dramatically. Pour the foam onto parchment in a thin layer and let set.

Break the honeycomb into shards and scatter over the glazed cake. Let everything set before slicing so the glaze firms up and shards adhere.