Prepare your oven and crust: Preheat your oven to 375°F (190°C). Place your pie crust in a 9-inch pie dish, crimping the edges decoratively. Refrigerate while preparing the filling.
Prepare the apples: Peel, core, and slice the apples into thin, uniform slices (about ⅛ inch thick). Toss them gently with lemon juice to prevent browning.
Make the custard filling: In a medium bowl, whisk together the eggs, heavy cream, sugar, flour, vanilla extract, and salt until smooth and well combined. The mixture should be pourable but have some body to it.
Arrange the apples: Remove the pie crust from the refrigerator. Layer the apple slices in concentric circles in the pie crust, slightly overlapping them for an attractive pattern. For extra flavor, brush the apples lightly with melted butter.
Pour the custard: Slowly pour the custard mixture over the arranged apples, allowing it to seep between the layers. The custard should come just below the top layer of apples.
Bake with protection: Place the pie on a baking sheet (to catch any potential overflow) and bake for 20 minutes. Then lower the temperature to 350°F (175°C) and continue baking for about 25-30 minutes more, until the custard is set in the center with just a slight wobble.
Cool properly: Remove from the oven and allow to cool completely on a wire rack for at least 2 hours before slicing. The custard needs time to fully set.
Optional finishing touch: For a professional shine, warm the apricot jam slightly and brush it over the top of the cooled pie.