Grease a 6-inch round cake pan, line the bottom with a parchment round, and grease the parchment.
Leave the crisper plate in the 4-qt glass container so the pan sits elevated.
Whisk the flour, sugar, baking powder, and salt together in a medium bowl.
In a separate bowl, whisk the melted butter, eggs, milk, and vanilla until smooth.
Pour the wet into the dry and stir just until no dry flour remains, 20 to 30 seconds. Do not overmix.
Pour into the prepared pan, filling no more than two-thirds. Level the top.
Dome a square of foil over the pan and crimp the edges down firmly so the fan can't lift it.
Set the pan on the crisper plate, install the adapter and PowerPod, select BAKE, and set 18 minutes. (Crispi Pro: 325°F.)
Remove the foil carefully. Reinstall the PowerPod and bake 5 to 7 more minutes, until golden and a toothpick in the center comes out clean.
Cool in the pan 10 minutes, then run a knife around the edge, invert onto a rack, and peel the parchment.
Cool completely, about 45 minutes, before frosting.