Preheat oven to 325 °F (163 °C). Line an 8×8‑inch baking pan with parchment, lightly spray to prevent sticking.

In a small saucepan over medium-low heat, melt butter and cook until it just begins to brown and become fragrant. Remove from heat promptly to avoid over-browning.

In a mixing bowl, whisk the browned butter, brown sugar, and honey until well combined and smooth.

Beat in the egg and egg yolk until fully incorporated. Stir in about 1 teaspoon flaky sea salt.

Gently fold in the flour until just combined—avoid overmixing to maintain tenderness.

Spread the batter into the prepared pan, smoothing the top. Sprinkle chopped pistachios across the surface, then lightly sprinkle remaining ¼ teaspoon sea salt.

Bake for 23–25 minutes, until edges are set and top is golden, but the center remains slightly soft.

Cool in pan for 10 minutes, then lift out by parchment and transfer to a wire rack to cool completely before slicing into bars.