Almond Filling

1. Place almonds, breadcrumbs, butter, sugar and almond extract in the base of a food processor and pulse until finely chopped, about 30 pulses. Transfer mixture to a bowl and set aside.

Rhubarb Filling

1. Place chopped rhubarb in a medium bowl. Remove 2 tablespoons of the sugar and set aside. Add remaining sugar to bowl with rhubarb, along with cornstarch and salt. Toss until well coated; set aside for 10 minutes.

To Assemble the Galette

1. Preheat oven to 425°F. Line a baking sheet with parchment paper. Set aside.
2. On a lightly floured surface, roll pie crust into a 13-14-inch disc. The crust does not have to be perfectly circular. Transfer to prepared baking sheet.
3. Brush the entire crust with egg wash then place the almond mixture in the center of the dough, leaving a 1 1/2-inch border. Gently press into a single layer. Add rhubarb mixture directly on top of almond mixture, including any sugar that dissolved.
4. Carefully fold the edges of the dough over the rhubarb filling, gently pressing each fold to seal. Brush the folds with more egg wash. Sprinkle the dough and exposed rhubarb filling with reserved 2 tablespoons of sugar. Refrigerate for 10 minutes.
5. Transfer baking sheet to oven and immediately reduce the temperature to 375°F. Bake until the crust is golden brown and the filling is bubbly, 45-55 minutes. Remove from oven and cool at room temperature for 10 minutes.
6. Microwave raspberry jam and water in a microwave-safe dish until bubbly, about 30 seconds, then stir to combine. Or, heat the jam and water in a small sauce pan on medium until melted and brushable. Carefully brush mixture over rhubarb. Cool galette another 50 minutes before slicing to serve. Store leftovers covered in the refrigerator for up to 3 days.