Brown-Butter Peach Oat Crumble Bars

Make it

Instructions

1. 01

   Heat the oven and prepare the pan

   Set a rack in the center of the oven and preheat to 175°C (350°F). Line a 23 cm (9-inch) square baking pan with parchment, leaving enough overhang on two sides to lift the bars out later. Set out a medium saucepan, two mixing bowls, a whisk, and a spatula. | Why: A centered rack and parchment help the bars bake evenly and release cleanly.

2. 02

   Brown the butter

   Melt 170 g unsalted butter in the medium saucepan over medium heat, swirling the pan often, for about 5–7 minutes. It will foam, then turn golden with amber flecks and smell toasted; remove it from the heat promptly so it does not burn. Pour it into a heatproof bowl and let it cool for about 10 minutes, until warm but not hot. | Why: Browning deepens the butter’s flavor, while a brief cool-down keeps the crumb mixture from becoming greasy.

3. 03

   Prepare the peach filling

   Rinse and dry 600 g ripe peaches, then remove the pits and cut the peaches into roughly 1 cm pieces; peel them only if their skins are tough. In a mixing bowl, toss the fruit with 60 g granulated sugar, 18 g cornstarch, and 1 tbsp lemon juice until the pieces are evenly coated. Set aside while you make the crumb mixture. | Why: Small, evenly cut pieces soften quickly, and cornstarch thickens the fruit juices as they bake.

4. 04

   Mix the oat crumb

   In the second mixing bowl, whisk together 220 g all-purpose flour, 120 g rolled oats, 150 g light brown sugar, ½ tsp ground cinnamon, and ¼ tsp fine salt. Pour in the cooled browned butter and stir with a spatula until no dry flour remains and the mixture forms moist, clumpy crumbs. Press about two-thirds of the mixture firmly and evenly into the lined pan to make the base; keep the remaining third loose for the topping. | Why: A firmly packed base holds together, while loose crumbs on top bake into a crisp layer.

5. 05

   Layer and bake

   Spread the peach mixture evenly over the crumb base, including any juice in the bowl. Scatter the reserved crumb mixture across the top in an even layer without packing it down. Bake on the center rack at 175°C (350°F) for 40–45 minutes, until the topping is deeply golden and the fruit is bubbling at the edges. If the center still looks wet and pale, bake for another 3–5 minutes and check again. | Why: Baking until the filling bubbles ensures the fruit thickener has activated and the bars will set as they cool.

6. 06

   Cool, slice, and serve

   Set the pan on a wire rack and cool the bars completely, about 2 hours, so the filling firms up. Use the parchment overhang to lift the slab onto a cutting board, then cut into 16 bars with a sharp knife, wiping the blade between cuts for neat edges. Serve at room temperature; store leftovers covered in the refrigerator for up to 4 days. | Why: Full cooling is the key to clean slices and a set, jammy peach layer.