Adjust an oven rack to the middle position and preheat the oven to 350 degrees.
Cover a 9-inch square baking pan with heavy duty aluminum foil. Push foil neatly into corners and up sides of the pan, using two pieces if necessary to ensure it overlaps all edges.
Spray foiled pan with nonstick cooking spray.
Place the flour, corn starch, confectioners’ sugar and salt in a bowl of a food processor fitted with the blade attachment. Pulse a few times to mix. Add the butter and pulse until the mixture resembles coarse meal with pea-size clumps of butter within.
Dump mixture into prepared pan and press firmly with your fingers into an even layer over the bottom. Refrigerate for 15 minutes, then bake until crust is set but not browned, about 17 minutes. Set on rack to cool. Leave oven on.
In a heavy medium saucepan over medium-low heat, combine butter, brown sugar, honey, vanilla and salt. Stir with a wooden spoon until sugar dissolves.
Turn up the heat and boil gently for 3 minutes. Stir in heavy cream and chopped pecans.
Pour pecan mixture over crust (it’s fine if crust is still warm). Bake until filling is bubbling and caramel in color, about 20 minutes.
Cool completely on rack.
To cut, use the foil overhang to lift baked square out of pan and onto cutting board. Loosen the foil from the edges, then cut with a sharp knife into 2-inch squares. Store finished pecan squares in air-tight container and serve at room temperature.