Pre-heat the oven to 350ºF. If your oven runs hot, or if it’s convection or gas, set to 325ºF instead. Grease and line a 8×8” square pan with parchment paper. Don’t use a glass pan because it can cook unevenly.

Mix the unsalted butter and white chocolate in a large bowl. Place the bowl in the microwave or over a double boiler to melt them together. Microwave for 15 to 30 second increments, stirring in between until the chocolate has melted completely with the butter. If using a double boiler, make sure the bowl is heat-proof, and place it over a pan with simmering water, and whisk the mixture until the chocolate and butter have melted together.

Add the granulated sugar and whisk to combine.

Add the eggs, one at a time to the bowl, whisking until combined before adding the next egg.

Then add the egg yolk along with the vanilla and almond extract, and whisk to combine.

Add the flour, almond flour, and salt to the bowl, mix on low to combine, or fold with a spatula.

Pour the blondie batter on the bottom of the prepared pan.

You will bake the blondies in two rounds. First for about 30 minutes, until the blondies look set around the edges and on top, but not fully baked through. If your oven runs hot or it is convection, it might take less time, like 25 minutes.

While the blondies bake for the first round, make the almond croissant topping

Melt the butter in the microwave. Add the sugar, whisk to combine.

Add the egg, the almond extract, and the vanilla, and mix.

Add the almond flour to the bowl and stir to combine.

Remove the blondies from the oven once they’ve baked for about 30 minutes.

Pour the almond croissant topping over them, spread on an even layer.

Sprinkle the sliced almonds on top.

Place the blondies back in the oven and bake for another 25 minutes.

Remove the blondies from the oven. Let them cool down before slicing and serving.

Sprinkle powdered sugar on top before serving.

Store at room temperature for up to 2 days, or in the fridge for up to 4 days.

They freeze well, in an air tight container or freezer bag for up to 2 months. Thaw in the fridge or on the counter for 30 min to an hour.