Preheat the oven to 350 and move one of the racks to the lowest setting.: The warm, slightly dry heat at the lowest rack helps the bottom crust bake thoroughly while the filling sets from the top down, producing an even texture. You should notice the oven reaching an even temperature and the oven light showing a steady glow, which signals stability. If your oven runs hot, consider placing an oven thermometer inside, because uneven heat can cause the filling to crack. A common mistake is skipping the rack adjustment, which can leave the crust underbaked while the top browns too quickly.
Line a 9 inch shallow pie plate with the refrigerated pie crust and crimp the edges.: Working with a chilled pie crust ensures the butter in the dough remains solid until baking, leading to flakier edges. Press the crust gently into the plate, trim excess, and crimp for a decorative finish. The crust should be cold to the touch; if it feels too soft, pop it in the fridge for ten minutes to firm up. Avoid overworking the dough, because handling it too much warms the butter and yields a tougher crust.
In a medium bowl, whisk together the sugar, cornmeal, flour and salt until well mixed.: As you whisk the dry ingredients, you will smell the faint sweetness of the sugar and notice the grain of the cornmeal against the flour, which indicates even distribution. This step ensures even texture and prevents clumps in the final filling. If you skip thorough mixing, pockets of cornmeal or flour can create gritty spots. A common misstep is using coarse cornmeal, which yields an unexpectedly coarse texture.
In a small bowl, beat the eggs, whisk in the melted and cooled butter, evaporated milk.: The beaten eggs should be smooth and slightly frothy, showing that air is incorporated for a lighter set. Adding the cooled butter and evaporated milk slowly helps maintain an even temperature, preventing the eggs from cooking. You will feel the mixture become silkier as it comes together. If you add hot ingredients, the eggs may scramble, so always ensure the butter has cooled. One trap is not whisking the eggs enough, which can lead to uneven texture later.
Zest one lemon before cutting all three in half and squeezing the juice out into a separate bowl. Pour the juice through a fine sieve to remove any seeds and pulp.: When you zest the lemon , the room fills with bright citrus oils, a sign of freshness. Squeezing and straining the juice removes any bitter pith or seeds, leaving a clean liquid that blends smoothly into the custard. A fine sieve will catch stray pulp, giving a glossy finish to the filling. If seeds slip through, fish them out promptly; leaving them in can ruin the texture.
Add the zest and the lemon juice to the egg mixture. Add all of the egg mixture including the lemon juice and zest into the medium sized bowl that contains the sugar mix. Mix well.: At this stage, the aroma becomes vibrant as the lemon zest melds with the beaten eggs , creating a fragrant custard base. Stirring the combined mixtures until they're uniform yields a smooth, slightly viscous batter. You should see a glossy sheen indicating proper integration. If the mixture looks separated or lumpy, whisk more thoroughly; lumps often mean the dry ingredients were not fully incorporated.
Pour the mixture into the pie shell and bake in the oven with the rack set at the lowest setting. Bake for 35 - 45 minutes. The pie is done when you jiggle the sides of the pie plate and the middle is only a little jiggly and the top is browned.: As the pie bakes, the kitchen will fill with a warm, lemony scent and the top will take on a light golden color. The sides will set first, leaving the center slightly wobbly, which is the correct doneness for a custard like this. You can gently jiggle the pan to test; a bit of movement in the center is desirable because it will continue to set while cooling. Avoid overbaking, because a dry, cracked surface means the custard has been cooked too long. If the edges brown too quickly, tent the crust with foil to prevent burning while the center finishes.