My great aunt used to bake this miraculous 4 ingredient dessert during the hardest times. It magically transforms into a sweet buttery custard-like center with a flaky crust that melts in your mouth.

This 4-ingredient water pie is one of those old-fashioned, make-do desserts that came out of the hardest times, when pantry shelves were bare but everyone still needed a little comfort. My great aunt used to bake this during lean years, turning the simplest staples—water, sugar, butter, and a basic pie crust—into a sweet, buttery, custard-like filling that settles into a flaky crust. As it bakes, the clear liquid thickens and turns translucent and creamy, with a golden, slightly cracked top that looks like you fussed far more than you did. It’s humble, budget-friendly, and perfect for when you want dessert without a long ingredient list.

Serve this water pie slightly warm or at room temperature so the center has time to set into that silky, custard-like texture. A dollop of whipped cream or a small scoop of vanilla ice cream makes it feel extra special without overpowering its gentle, buttery flavor. I like to pair it with a cup of coffee or hot tea after dinner, or a glass of cold milk for the kids. It’s lovely on its own as a simple weeknight dessert, but it also fits right in on a holiday table next to heavier pies since it’s lighter and not overly sweet.

Servings: 8

1 unbaked 9-inch pie crust (homemade or store-bought, fitted into an aluminum pie tin)

Preheat your oven to 400°F (200°C). Place the unbaked 9-inch pie crust, already fitted into an aluminum pie tin, on a baking sheet to make it easier to move in and out of the oven.

In a medium bowl or large measuring cup, stir together the hot water and granulated sugar until the sugar is mostly dissolved. It doesn’t have to be perfect, but you don’t want big sugar crystals sitting at the bottom.

Slowly pour the sugar water mixture directly into the unbaked pie crust, filling it almost to the top but leaving a little room so it doesn’t spill when you move it.

Gently drizzle the melted, slightly cooled butter over the top of the liquid in the crust. Don’t worry if it looks like the butter is just floating on top or forming little pools—that’s part of the magic. As it bakes, the butter will help create that custard-like center and a lightly caramelized top.

Carefully transfer the baking sheet with the pie to the oven. Bake at 400°F (200°C) for 15 minutes to help set the crust and start the filling.

After 15 minutes, reduce the oven temperature to 350°F (175°C) without opening the oven door if you can help it, and continue baking for another 35–45 minutes. The pie is done when the crust is golden brown, the top is a deeper golden color with a few small cracks, and the center looks mostly set but may still have a slight jiggle when you gently nudge the pan.

Remove the pie from the oven and place it on a cooling rack. The filling will look a bit wobbly and translucent at first, but it will thicken and turn creamy as it cools. Let it cool at least 2–3 hours, or until the center is fully set and slices cleanly.

Once cooled, slice the pie into wedges right in the aluminum pie tin. The flaky crust should hold a soft, custard-like, buttery filling with a lightly caramelized, slightly cracked top. Serve as is, or with a bit of whipped cream if you like.

Because this pie is so simple, small changes can really make it your own while still keeping that sweet, buttery, custard-like center. For a touch of warmth, stir 1 teaspoon of vanilla extract into the hot water and sugar mixture before pouring it into the crust—this keeps the ingredient list simple but gives the pie a cozy flavor. If your family likes a hint of spice, you can lightly sprinkle ground cinnamon or nutmeg over the top after you drizzle on the butter; it will bake into a soft, crackly layer. For picky eaters who prefer things less sweet, reduce the sugar to 3/4 cup and add a spoonful of whipped cream on top of each slice to balance it out. If you’re worried about the crust browning too quickly, loosely cover just the edges with strips of foil halfway through baking. To help the filling set nicely, be sure to give the pie plenty of cooling time—this is a good one to make earlier in the day so it’s ready by dessert. Leftovers keep well, covered, at room temperature for a day or in the fridge for up to 3 days; you can gently warm slices in the microwave for a few seconds to bring back that soft, comforting texture.