In a saucepan, whisk together the sugar, cornstarch, and salt. Add the milk, cream, and egg yolks and whisk until smooth.

Set over medium heat and stir until thickened — about 5–7 minutes.

Remove from heat and stir in the butter and vanilla.

Let the custard cool completely (it thickens as it cools). Stash it in the fridge while you get the dough ready.

Mix the flour, sugar, and salt in a bowl. Cut in the cold butter until everything looks like coarse crumbs.

Drizzle in the ice water just until the dough comes together.

Divide into two discs and chill for about 30 minutes.

(Or unwrap your store-bought dough. I won’t tell.)

Roll the dough to about ⅛ inch thick and cut into rectangles — roughly 3x5 inches.

Spoon 1–2 tablespoons of custard onto half of the rectangles, then top with the rest.

Press edges with a fork to seal.

Brush the tops with egg wash and cover them with rainbow jimmies and coarse sugar.

Bake at 375°F for 18–22 minutes, until golden and lightly puffed.

Let them cool until they’re warm but not lava-hot.

Enjoy with coffee, tea, or standing over the counter like a gremlin — your choice.