Preheat the oven to 350°F (175°C). Line an 8x8-inch pan with parchment, leaving an overhang for easy removal.

In a mixing bowl, beat the cold butter pieces with the granulated sugar until the mixture is light but still a bit crumbly. Add vanilla and a pinch of salt.

Stir in the flour until the dough just comes together into crumbs. Press the dough firmly and evenly into the prepared pan. Smooth the top with a spatula.

Chill the crust in the fridge for 15–20 minutes to reduce shrinkage and help create a flakier texture.

Bake the chilled crust for 18–22 minutes, until it’s a pale golden color and feels set. Remove from oven and let it cool slightly while you toast the walnuts.

Toast the walnuts in a dry skillet over medium heat for 3–5 minutes, stirring, until fragrant and lightly browned. Watch closely to avoid burning.

In a small saucepan, combine 3 tablespoons butter, 1/3 cup honey, and 2 tablespoons light corn syrup (or extra honey). Warm until melted and glossy. Add a splash of cream if using, and a pinch of salt. Stir in the toasted walnuts and cook 1–2 minutes to coat.

Immediately spread the walnut-honey mixture over the baked shortbread, pressing lightly to ensure contact. Return the pan to the oven for 8–10 minutes to set the topping.

Let cool completely on a wire rack. For cleaner slices, refrigerate for 30 minutes before slicing into bars. Dust with powdered sugar just before serving.