Position an oven rack in the center of the oven and preheat oven to 350 degrees. Butter a 13x9-inch baking pan. Line the bottom and the 2 short ends with a 20-inch-long piece of aluminum foil, pleating the foil to fit and let the excess foil hang over the ends. Lightly butter the foil.
To make the shortbread layer: In a medium bowl, mix the flour, butter and sugar with an electric mixer set on low speed just until combined and crumbly. Do not mix into a dough; it should remain crumbly. Press firmly and evenly into the prepared pan. Bake until golden brown, about 30 minutes. Remove from the oven and let stand on a wire cooling rack. Leave the oven on.
To make the topping: In a medium saucepan, bring the butter, brown sugar, honey, maple syrup and heavy cream to a boil, stirring until the butter melts. Boil for 2 minutes. Remove from the heat and stir in the pecans. Pour and spread the pecan mixture over the crust.
Return to the oven and bake until the pecan mixture is bubbling and golden brown around the edges, about 30 minutes. Let cool completely in the pan on a wire cooling rack.
Run a dinner knife around the edges of the shortbread to release it. Lift up the foil "handles" and remove the shortbread from the pan. Using a long sharp knife, cut into 24 rectangles.