1-First Step: Preheat and Prep (Mise en place) Preheat your oven to 350°F and line an 8×8 inch baking pan with parchment paper so you can lift the blondies out easily. If you have an insulated or glass pan, reduce or extend bake time slightly; glass pans often need a few extra minutes. Gather all ingredients and measure them before you begin to keep the process smooth.

2-Second Step: Make the Frangipane In a small bowl or the bowl of a stand mixer, cream together 1/2 tablespoon of the butter with the 1/4 cup granulated sugar until smooth. Add 1 egg yolk, 1/4 teaspoon vanilla extract, 1/4 teaspoon almond extract, and 1/4 teaspoon orange zest if using. Mix briefly to combine. Fold in 2/3 cup almond flour and a pinch of salt until you get a thick paste. The frangipane should be spreadable but not runny; set it aside while you make the blondie batter.

3-Third Step: Make the Blondie Batter In a large bowl, beat together 1/2 cup softened butter and 1 cup packed light brown sugar until well combined and somewhat glossy. Add 1 large room-temperature egg and mix until incorporated. Stir in 1/4 teaspoon almond extract and 2 teaspoons vanilla extract until the batter is smooth. Fold in the dry ingredients: 1 and 1/3 cups all-purpose flour, 1/4 teaspoon baking powder, 1/4 teaspoon salt, and 1/3 cup almond flour. Mix until just combined to avoid a tough texture. A few streaks of flour are okay; gentle handling keeps the blondies tender.

4-Fourth Step: Assemble in the Pan Spread the blondie batter evenly into the prepared 8×8 inch pan, smoothing the top with an offset spatula or the back of a spoon. Dollop the frangipane paste over the batter in small spoonfuls. Use a wooden skewer or the tip of a knife to swirl the frangipane into the top layer in pretty patterns, but don’t overmix; you want visible swirls of almond cream. Sprinkle 1/2 cup sliced almonds evenly over the top for crunch and a bakery look. If you like extra almond flavor, scatter a few additional pinches of almond flour across the top before baking.

5-Fifth Step: Bake Bake in the preheated 350°F oven for about 30 minutes. Check for doneness by looking for set edges and a center that is slightly firm to the touch but still gives a little under gentle pressure; this keeps the blondies gooey. If using a glass pan, check around 28 minutes and add a few extra minutes if needed. For a slightly more set center, bake 32 to 35 minutes.

6-Final Step: Cool, Dust, and Slice Allow the blondies to cool completely in the pan before dusting with powdered sugar and slicing into 16 squares. Cooling is important: the frangipane firms up and bars cut cleanly. Use parchment to lift the slab from the pan for neat cutting. Serve slightly warm or at room temperature.