Rhubarb Streusel Pie

Makes 1 9-inch pie

Ingredients:

• ½ recipe Double Crust Pie Dough, chilled
• 2 Tbsp    Rolled oats
• 6 cups Diced fresh rhubarb
• 1 ¾ cups Sugar
• 3 Tbsp    Tapioca starch (also called tapioca flour)
• 1 tsp Vanilla extract

Streusel:

• 1 cup All-purpose flour
• 1/3 cup    Rolled oats
• ¼ cup Packed light brown sugar
• 1 tsp Ground cinnamon
• ½ tsp Salt
• ½ cup Cool unsalted butter, cut into pieces

1. Pull out the chill pie dough 30 minutes before rolling. Preheat the oven to 375 F. Lightly dust the bottom of a 9-inch pie plate with flour and place it on a parchment or foil-lined baking tray.
2. On a lightly floured surface, roll out the pastry to just under ¼-inch thick.  Lift the rolled dough and line the pie plate.  Trim away any excess dough that hangs more than an inch over the edge of the pie plate.  Tuck this outside bit of pastry under and pinch this crust into a decorative pattern.  Sprinkle the oats in the bottom of the pastry and chill it while preparing the filling and streusel.
3. For the filling, toss the rhubarb with the sugar, tapioca starch and vanilla. Spoon this into the prepared pie shell.
4. To prepare the streusel, stir the flour, oats, brown sugar, cinnamon and salt to combine.  Cut in the butter until the mixture is a rough crumbly texture. Sprinkle the streusel over the rhubarb, then bake the pie on the prepared tray, for 20 minutes, then reduce the oven temperature to 350 F and continue to cook the pie for 40 to 45 minutes more, until the outside crust is evenly browned and the rhubarb filling is bubbling at the edges.  Cool the pie for at 3 least hours before slicing, or chill to serve cold.