Finely ground pecans add nutty richness to the dough that doubles as the bottom crust and top crumble layer of these yummy bars. Cooking down fresh peaches for the filling concentrates their sweet floral flavor and adds more intensity than a jar of prepared jam.
Preheat the oven to 350˚ F. Line a 9-by-13-inch baking pan with foil and butter the foil.
Cook the peaches with the water and golden syrup in a saucepan until thick and jammy, mashing if needed, about 12 minutes.
Combine the flour, pecans, confectioners' sugar, baking powder and salt in a bowl. Work in the cut-up butter until moist clumps form.
Press two-thirds of the dough into the pan pan. Spread the peach mixture on top and sprinkle with the remaining dough. Bake at 350˚ F until browned, 40 to 45 minutes. Let cool completely in the pan, then lift out of the pan using the foil. Cut into bars.