Prepare oven: Preheat oven to 425°F with 1 rack on middle rack for crust, and 1 rack on lower third for pie.
Fit piecrust to pie plate: Fit piecrust in a 9-inch pie plate according to package directions; fold edges under, and crimp.
Parbake piecrust: Line crust with aluminum foil or parchment paper. Fill with pie weights or dried beans. Bake in preheated oven on middle rack for 5 minutes. Remove from oven; remove weights and foil.
Finish parbake, and cool: Return crust to oven; bake on middle rack until lightly browned on edges and golden on bottom, 3 to 4 minutes. Transfer to a wire rack; let cool completely, about 30 minutes.
Make pie filling: Reduce oven temperature to 325°F. Whisk together sugar, butter, flour, cornmeal, lemon zest, and lemon juice in a large bowl until combined. Add eggs; whisk until smooth.
Add pie filling to crust: Pour mixture into prepared piecrust.
Bake pie: Bake at 325°F on lower rack until lightly golden and set, 40 to 45 minutes, covering edges with aluminum foil during final 10 to 15 minutes to prevent over-browning, if needed. Remove from oven; let cool completely on a wire rack, about 2 hours. Garnish pie with sifted powdered sugar, and serve with whipped cream.
