Preheat oven to 350 degrees F. Spray a 9x13-inch baking dish with nonstick spray, line with parchment paper, leaving overhang. Spray the parchment.
To make the Snickerdoodle crust, in a medium bowl, whisk to combine the flour, cinnamon and salt. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed until light and well blended. Reduce the speed to low and add the flour mixture, stirring until just combined, then stir in the vanilla extract.
Press the dough in an even layer into the prepared baking dish and refrigerate for 20 minutes. Dock the dough with a fork, then bake for about 20 minutes until the edges are starting to turn golden. Remove and let cool while you make the filling.
To make the filling, in a small bowl, whisk to combine the flour, baking powder and salt. In a medium bowl, whisk to combine the eggs, sugar, lemon zest and lemon juice. Add the flour and whisk to combine.
Pour the filling over the crust and bake until set, about 28-30 minutes. Transfer to a wire rack and let cool completely, then refrigerate until completely set, about 1 hour and up to overnight.
Use the edges of the parchment paper to lift the lemon bars from the pan. Place 8-10 long wooden skewers randomly over the top and dust over confectioners sugar. Cut into 2-inch squares and serve.