Crack the eggs into a wide, shallow dish—such as a pie plate or a 13- x 9-inch baking dish for larger batches—and beat them thoroughly. Pour in the whole milk, sprinkle in the sugar, and add the vanilla extract, whisking until all elements are uniformly incorporated.

Place 1 tablespoon of butter into a large skillet, between 12 to 14 inches in diameter, and heat it over MEDIUM. Submerge a slice of brioche in the custard, turning it to coat both sides generously. When the butter has fully melted and starts to foam, lay the soaked brioche into the pan. Continue dipping and adding as many slices as can fit without crowding.

Sauté each piece for 3 to 4 minutes per side until each surface is beautifully golden brown. Move the finished French toast to a platter and keep it warm—either by using a warming tray or placing it on a baking sheet in a 200°F oven.

Wipe out the skillet with a paper towel and repeat the process with the remaining butter, bread, and custard mixture.

Serve the toast immediately, complemented by the warmed maple syrup and a generous helping of fresh berries.