Kaiserschmarrn

Stir 1/3 cup raisins and 2 tablespoons white rum together in a small bowl. Let sit, stirring occasionally, while you prepare the batter and start cooking the pancake.

Whisk 3/4 cup whole milk, 2 tablespoons of the granulated sugar, 2 cold large egg yolks, 2 teaspoons vanilla extract, and 1/2 teaspoon kosher salt together in a large bowl until the sugar is dissolved.

Whisk in 1/2 teaspoon baking powder. Whisk in 3/4 cup all-purpose flour until smooth.

Beat 4 cold large egg whites in a stand mixer with the whisk attachment on medium speed until the whites are broken up, about 30 seconds. With the mixer still running, slowly stream in the remaining 2 tablespoons granulated sugar, about 30 seconds. Increase the speed to medium-high and beat until opaque and very foamy and aerated, about 1 minute more. Increase the speed to high and beat until glossy, doubled in volume, and just reaches a stiff peak, about 2 minutes.

Using a whisk, fold 1/4 of the whipped egg whites into the milk mixture to lighten. Add the remaining meringue and fold together with the whisk until halfway combined. Switch to a flexible spatula and finish folding together until just combined and no streaks of meringue or the milk mixture remain.

Melt 2 tablespoons of the unsalted butter in a 12-inch nonstick skillet over medium-low heat. Swirl the pan to coat evenly with butter.

Add the batter and smooth into an even layer. Cover and cook until the pancake is set around the edges (it will still be runny all over the top) and golden underneath (it will be lighter around the edges and likely have more color in the center where the heat is more direct), 4 to 7 minutes. You can use a flexible spatula to loosen and lift around the edges to check.

Meanwhile, drain the raisins if using. Once set around the edges, scatter the raisins evenly over the pancake.

Remove the pan from the heat. With the pancake still in the pan, use a firm-edged spatula to cut the pancake into wedges manageable enough for you to flip. Flip each wedge over, using another spatula to help if needed. It’ll be messy, might not be evenly browned, and batter may get on the cooked side — that’s all OK.

Return to medium-low heat and cook until the pancake is just set and golden to golden-brown on the bottom, 1 to 4 minutes.

Using the spatula or carefully with two forks, cut and pull the pancake wedges apart into haphazard, bite-sized pieces. Toss and cook until any remaining wet batter is just set, about 1 minute more.

Push the pancake pieces to one side of the pan. Increase the heat to medium. Add the remaining 2 tablespoons unsalted butter and 2 tablespoons granulated sugar to the empty side. Once the butter is melted, toss the pancake pieces in the butter and sugar mixture. (The sugar will crystallize onto the pancake pieces.) Spread back into a single layer.

Cook, flipping the pieces occasionally, until the sugar caramelizes onto the pancake and turns golden-brown, 4 to 8 minutes.

Transfer to a serving platter if desired, and dust with powdered sugar. Serve with applesauce, plum compote, fruit sauce, or jam if desired.

Substitutions: The raisins can be soaked in fruit juice or warm water instead.Make ahead: The raisins can be soaked up to 24 hours ahead; cover the bowl.Storage: Kaiserschmarrn is best eaten right away, but leftovers can be refrigerated in an airtight container for up to 3 days. They will not be as pillowy or have the same caramelized crust as when first made.