1-First Step: Prep and pan setup Preheat your oven to 350°F. Line an 8×8 inch baking pan with parchment paper, leaving an overhang on two sides to lift the blondies out easily after baking. Gather and measure all ingredients so everything is within reach. Softened butter should be at room temperature for easy creaming, and eggs should be at room temperature to help the batter come together smoothly.

2-Second Step: Make the frangipane (almond filling) This almond paste adds the croissant-like creaminess that makes these blondies special. * Cream together 1/2 cup softened butter and 1/4 cup granulated sugar using a hand mixer or stand mixer on medium speed until light and slightly fluffy, about 1 to 2 minutes. * Mix in 1 egg yolk, 1 teaspoon vanilla extract (from the 2 teaspoons total) and 1/4 teaspoon almond extract, plus 1/4 teaspoon orange zest if you are using it. The orange zest is optional but adds a bright note reminiscent of some almond croissant recipes. * Fold in 2/3 cup almond flour with a pinch of salt until a soft paste forms. Set the frangipane aside while you make the blondie batter.

3-Third Step: Make the blondie batter The blondie base is chewy, buttery, and lightly nutty thanks to a bit of almond flour. * In a large bowl, beat 1/2 cup softened butter with 1 cup packed light brown sugar until well combined and slightly glossy, about 2 minutes. * Beat in 1 whole egg and 1/4 teaspoon almond extract, then add the remaining 1 teaspoon vanilla extract. Mix until incorporated. * Gently stir in 1 and 1/3 cups all-purpose flour, 1/4 teaspoon baking powder, 1/4 teaspoon salt, and 1/3 cup almond flour. Mix just until combined; do not over-mix or the blondies may become tough.

4-Fourth Step: Assemble and swirl Layering and swirling creates the signature look and taste. * Spread the blondie batter evenly into the prepared 8×8 pan, smoothing the top with a spatula. * Drop small dollops of the frangipane evenly across the blondie batter. Use a skewer, toothpick, or the tip of a knife to swirl the frangipane into the top layer create pretty marbling but avoid fully mixing it in. * Sprinkle 1/2 cup sliced almonds over the top for crunch. Press them in gently so they stick during baking.

5-Final Step: Bake, cool, and serve * Bake at 350°F for about 30 minutes, or until the edges are set and the center is slightly firm but still a bit soft when touched. Baking time varies slightly by oven and if you use a glass dish it may take a few extra minutes. * Allow the blondies to cool completely in the pan on a wire rack this helps them set and makes slicing clean squares easier. Once cool, lift them out using the parchment overhang, dust with powdered sugar if desired, and slice into 16 squares.