Slices Recipe

Prepare oven and pan

Preheat the oven to 350°F (175°C). Line an 8x8-inch square baking pan with parchment paper, leaving an overhang on two sides to lift the slices out after baking.

In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt until evenly distributed.

Cut the cold, cubed butter into the flour mixture using a pastry cutter, two forks, or your fingertips until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

In a small bowl, beat the egg with the vanilla extract. Add the egg mixture to the flour-butter mixture and stir gently until the dough comes together. It will be slightly crumbly but should hold when pressed. If too dry, add 1 teaspoon cold water at a time until it holds.

Press about two-thirds of the dough evenly into the bottom of the prepared pan to form a compact crust. Use the bottom of a measuring cup to help pack the dough evenly. Reserve the remaining dough for the topping and edges.

Bake the crust in the preheated oven for 12–15 minutes, or until it is just set and very lightly golden. Remove from the oven and let it cool slightly while you prepare the filling.

In a small bowl, stir the jam with the lemon juice and lemon zest to loosen it and add brightness. If your jam is thick, microwave it for 10–15 seconds to make it spreadable, or whisk vigorously until smooth.

Spread the jam mixture in an even layer over the warm baked crust using an offset spatula or the back of a spoon. Leave a small border so the jam does not run when topping is added.

In a medium bowl, combine the rolled oats, brown sugar, ground cinnamon, and sea salt. Pour the melted butter over the oat mixture and stir until the mixture is evenly moistened and holds together when pressed.

Crumble the reserved base dough with your fingers into coarse pieces and scatter these pieces evenly over the jam layer. Then sprinkle the oat crumble mixture on top, pressing lightly so it adheres but still remains crumbly. Aim for an even coverage.

Bake the assembled bars for 18–22 minutes, or until the topping is golden brown and the jam is bubbling slightly at the edges. Rotate the pan halfway through baking for even color.

Remove from the oven and place the pan on a wire rack. Let the bars cool completely in the pan (at least 1 hour) so the jam sets and the bars firm up. For faster setting, you can refrigerate for 30–45 minutes once cooled to room temperature.

Using the parchment overhang, lift the cooled slab from the pan and place it on a cutting board. Trim any uneven edges if desired.

Cut into 12 equal rectangular slices (3 by 4 grid) or into 9 larger squares, using a sharp knife wiped between cuts for clean edges.

If using, dust the slices lightly with powdered sugar and sprinkle chopped toasted almonds or walnuts on top for texture.

Store leftover slices in an airtight container at room temperature for up to 3 days or refrigerated for up to 7 days. For best texture, allow chilled slices to come to room temperature before serving, or warm briefly in a low oven.