Instructions: Preheat the Oven: Preheat your oven to 400°F (200°C).If using a homemade or store-bought pie crust, place it in a 9-inch pie dish. Crimp or flute the edges as desired.
Prepare the Rhubarb: Rinse the rhubarb stalks and trim off any leaves. Chop the rhubarb into small pieces, about 1/2-inch in size.
Pour the Custard Filling: Pour the custard mixture over the rhubarb in the pie crust, ensuring that the rhubarb is evenly coated.
Bake and Reduce Oven Temperature: Place the pie in the preheated oven and bake for 10 minutes. After 10 minutes, reduce the oven temperature to 350°F (175°C) without opening the oven door.
Continue Baking: Continue baking the pie for an additional 40 to 45 minutes, or until the custard is set and the crust is golden brown.
Cool and Serve: Remove the pie from the oven and let it cool on a wire rack for at least 1 hour before serving. Serve slices of rhubarb custard pie at room temperature or chilled, optionally topped with whipped cream or a scoop of vanilla ice cream.