Preheat oven to 350ºF.: The kitchen will start to smell warm and faintly sweet as the oven reaches temperature, and preheating ensures an even bake from the moment the pie enters. Doing this first is important because the custard sets best with steady heat, not fluctuating temperature. A common mistake is placing the pie in a cold oven, which can cause an uneven set and longer baking time. Use an oven thermometer if your oven runs hot or cool, and wait until it reads 350 degrees so the crust bakes and the filling sets properly.
Beat together cream cheese, 1/4 cup sugar, and 1 egg at low speed of an electric mixer until smooth. Spread cream cheese mixture in bottom of pie crust.: You will feel the texture change as the cream cheese becomes silkier and lighter; the mixture should be lump free and glossy. Working at low speed prevents over aeration, which can create fissures during baking. Spread the mixture evenly so the top is level, which helps the custard layer sit uniformly above it. Avoid using cold cream cheese or high mixer speed, both of which cause lumps and air pockets; if you see streaks of unmixed cheese, pause and scrape the bowl until completely smooth.
Whisk together 1 cup sugar, 2 eggs, melted butter, milk, lemon rind, lemon juice, flour, cornmeal and salt. Pour over cream cheese mixture.: As you whisk, notice the batter become shiny and homogenous, with the lemon aroma intensifying from the oils in the rind. The melted butter and milk give the custard a satiny sheen, while the flour and cornmeal add subtle body. Pour slowly over the cheesecake layer so it settles gently and does not disturb the base. If you whisk too vigorously you will incorporate bubbles that may leave pinholes; a gentle, steady motion gives a smoother bake. Ensure the lemon juice is fresh for the brightest flavor, and scrape the bowl so no flour pockets remain.
Bake for 35 to 40 minutes, until set. Remove from oven and cool completely on wire rack.: During the bake the top will move from glossy to slightly matte and will have a faint jiggle in the center, which is exactly what you want. The aroma of lemon will strengthen and the edges may take a faint color, indicating the custard has set. Cooling on a wire rack prevents trapped steam and keeps the crust crisp. A common mistake is overbaking; that leads to a dry texture and cracks. Test by gently shaking the pie, the center should wobble a little but not be liquid. Remove promptly at doneness and allow the residual heat to finish setting.
Refrigerate until ready to serve.: Chilling lets the layers firm and the flavors meld; the cream cheese layer becomes denser and the custard chills into a clean slice. Refrigeration also improves texture, turning a warm custard into a sliceable pie with a silky mouthfeel. Avoid serving too soon, as the filling may be too soft to cut neatly. If the pie seems overly firm after chilling, let it sit at room temperature for a short time before slicing for a creamier mouthfeel.
