For the Rhubarb Custard Pie

• Preheat the oven to 375°F and position a rack in the center. Line a sheet pan with parchment paper and place the frozen crust in the center. Cover with foil and fill with pie weights.
• Bake the crust for 25 minutes. While the crust is baking, whisk together the egg, water, and salt in a small bowl for the egg wash and toss the rhubarb with ¼ cup of granulated sugar.
• After 25 minutes, remove the sheet pan from the oven, lift out the pie weights and foil. Use a pastry brush to coat the bottom and sides of the pie crust (not the crimped border) with egg wash, then bake uncovered for an additional 5 minutes.
• Cool the crust slightly on a wire rack for at least 10 minutes while preparing the custard filling.
• Whisk together the remaining 1 ¼ cups sugar, flour, eggs, butter, and cream until well combined. Pour the filling into the prepared crust and scatter the rhubarb over the top, discarding any liquid.
• Bake for 60 to 65 minutes until the edges of the filling are set but the center still wobbles slightly. Cool on a wire rack.
• Serve warm or at room temperature. The pie can be stored at room temperature until ready to serve and then refrigerated for up to 3 days.