1. For rhubarb filling: In a large pot, toss the sliced rhubarb, vanilla, and 1/2 cup of the sugar to combine. Cook over medium, tossing occasionally, until rhubarb starts to soften slightly, 5 to 7 minutes.

2. In a small bowl whisk the remaining 3/4 cup sugar, the cornstarch, nutmeg, and a pinch of fine sea salt to combine. Sprinkle sugar mixture evenly over rhubarb and mix well to combine. Cook, stirring frequently, until mixture gently bubbles from the center of the pot. Let cool completely before preparing the pie.

3. For the streusel: In a medium bowl stir the oats, all purpose flour, whole wheat flour, brown sugar, baking powder, cinnamon, and 1/4 teaspoon fine sea salt to combine. Rub butter into the flour mixture with your fingers until the mixture forms large clumps.

4. Preheat oven to 375°F. Place pie plate with the parbaked piecrust on a parchment-lined baking sheet. Spoon rhubarb filling evenly into the crust. Top with the streusel.

5. Bake until filling bubbles and crust and streusel are deeply and evenly golden brown, 45 to 55 minutes. Cool completely. If desired, serve with whipped cream or ice cream. Serves 8.

Erin's All-Buttah Piecrust

1. In a medium bowl whisk together flour and salt. Using your hands, toss butter through flour until each piece is well-coated. Cut butter into flour by pressing butter between your fingers and thumbs, flattening the cubes into big shards. For a flaky crust, mix until butter pieces are about the width of walnut halves. For a sturdier crust (for custard pies and for use with decorative techniques), mix until the butter is about the size of peas.

2. Make a well in center of flour mixture. Start by adding 1/4 cup ice water and tossing the flour mixture gently (rather than stirring) to moisten and incorporate the water without overworking the flour. Continue adding water, 1 to 2 tablespoons at a time, and tossing until dough comes together. (Dough should hold together easily without feeling wet or sticky.)

3. Form dough into a disk and wrap tightly in plastic wrap. Refrigerate at least 30 minutes and up to overnight.

4. Once well chilled, roll out dough on a lightly floured surface until it's about 1/8-inch thick. Press firmly and evenly, rotating the dough as you work to prevent sticking without adding too much flour. (Ideally dough will also be about 1 inch wider than your pie plate on all sides.)

5. To transfer dough to pie plate, starting at one end of dough, wrap it around the rolling pin. Lift pin to edge of pie plate and unfurl the dough. Press dough into the base of the pie plate and trim excess dough to 1/2 inch around outside edge of pie plate. Tuck dough under to be flush with the outer rim of pie plate. Crimp edges as desired, then refrigerate for at least 30 minutes.

6. To parbake: Use a fork to prick chilled crust all over base and sides. Cut a square of parchment paper slightly larger than pie plate and press it into base of chilled crust. Fill crust with pie weights (such as dried beans) to brim, making sure weights are flush against sides. Place pie plate on a parchment paper-lined baking sheet. Bake on bottom rack of 425°F oven (preferably on a preheated baking stone) 12 to 15 minutes or until outer edge begins to brown. Remove parchment and pie weights and bake 2 to 3 minutes more or until bottom crust appears set. If crust puffs at any point, prick air bubble with a fork to deflate. Let cool completely before filling. Makes one single crust.

Strawberry-Rhubarb Pie

Replace 3 cups of the sliced rhubarb with 3 cups quartered fresh strawberries. Add an additional 2 tablespoons cornstarch in Step 2.Nutrition analysis per serving: 472 calories, 5 g protein, 74 g carbohydrate, 18 g total fat (11 g sat. fat), 46 mg cholesterol, 4 g fiber, 39 g total sugar, 12% Vitamin A, 39% Vitamin C, 226 mg sodium, 6% calcium, 11% iron

The pie is best eaten the same day it's made. Store leftovers at room temperature, covered in plastic wrap.

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You can substitute frozen sliced rhubarb for the 6 cups fresh rhubarb (no need to thaw). Cook about 10 minutes in step one.

Make dough, wrap tightly, and refrigerate up to 2 days. For longer storage, wrap in plastic wrap then heavy foil and freeze up to 3 months. Thaw overnight in refrigerator and let stand at room temperature to soften slightly.

Cinnamon Crust

Add 1 Tbsp. ground cinnamon and 1/2 tsp. freshly grated nutmeg to the flour.

Gingerbread Crust

Add 1 tsp. ground cinnamon, 3/4 tsp. ground ginger, 1/2 tsp. ground allspice, and 1/4 tsp. ground cloves to the flour.