This is a truly easy, incredibly delicious pie that looks like it takes much more effort than it actually does. Once you start eating it, none of that matters, either.
Easy-As-Pie Rhubarb Pie
Put the bottom piecrust into a 9-inch pie pan. If using a frozen prepared shell, allow to thaw at room temperature for about 15 minutes.
Mix all of the remaining ingredients together and let them stand for 15 minutes, stirring occasionally.
Preheat the oven to 450°F.
Pour the filling into the piecrust and cover with a top crust or lattice, if using. Sprinkle with cinnamon.
Bake for 10 minutes at 450°F, then decrease the heat to 350°F and continue to bake for 45 to 50 minutes, or until the filling is bubbly.
Cooking Note: If you prefer, you may use a graham cracker crust.