Preheat your oven to 350°F (180°C) and line a square baking pan (8'x8') with parchment paper, leaving some overhang on the sides. The parchment makes it much easier to lift the baked cookie bar out of the pan for slicing.

Add the almond flour, granulated sugar, melted butter, and almond extract to a small bowl.

Stir until everything is evenly combined and you have a thick, spreadable almond mixture.

Set aside while you prepare the cookie dough.

Add the melted and cooled butter and brown sugar to a large mixing bowl. Whisk until well combined.

Add the milk, vanilla extract, and almond extract and mix again.

Add the all-purpose flour, almond flour, sourdough discard, and baking powder.

Stir until you have a thick cookie dough. Don't overmix once the flour has been incorporated.

The dough should be thick enough to spread into the pan. If it seems unusually loose, add a little extra all-purpose flour. If it's too dry, add a little extra milk.

Press or spread about half of the cookie dough evenly into the prepared pan.

Spread the almond frangipane over the dough, leaving a small border around the edges.

Add the remaining cookie dough on top.

Because the dough is thick, the easiest way to do this is to flatten portions of the dough between your hands before placing them over the frangipane. Gently press and smooth the pieces together until the almond layer is covered.

Don't worry if the top isn't perfectly smooth. It will even out as it bakes.

Add the sliced almonds

Scatter the sliced almonds evenly over the top of the cookie dough.

Gently press them into the surface so they stay in place during baking.

Bake at 350°F (180°C) for 30-35 minutes or until the cookie bar is golden brown around the edges and the center is set but still slightly soft.

The key is not to overbake it. The center will continue to firm up as the cookie bar cools, and taking it out while it is still slightly soft is what gives you that chewy, dense cookie-bar texture.

Cool completely

Allow the cookie bar to cool completely in the pan before slicing.

This is important. The almond filling and cookie layer need time to firm up, and slicing while the bars are still warm can make the layers smear or fall apart.

Once completely cool, use the parchment paper to lift the entire slab from the pan.

Using a sharp knife, cut the slab into 12 squares or less (if you want bigger portions).

For the cleanest cuts, wipe the knife between slices.

Finish with a generous dusting of powdered sugar just before serving.