Recording it here because it turned out really well. It was a blending of four different recipes I found online.

Raspberry Rhubarb Pie

4 1/2 cups chopped rhubarb

2 6 oz packages

1 cup sugar

1/2 tsp cinnamon

1/4 cup + 2 tablespoons flour

1 Tbsp cornstarch

2 Tbsp butter (cut into 1/4" cubes)

1 Tbsp butter melted

1 tsp raw sugar

2 pre-made Pillsbury pie crusts

Pre heat oven to 350 deg F

Mix sugar, flour, cornstarch, and cinnamon and pour into bowl atop chopped rhubarb.

Mix in butter cubes, and gently fold in raspberries.

Lightly butter 9" deep dish pie dish and unroll one pie crust into pie dish.

Place all of the filling into the pie dish, pressing it down so it will fit.

Cover with other pie crust, and crimp the edges together.

Cut 8 short radial slits in the top crust.

Bake at 350 deg F for 45 minutes.

Brush top crust with melted butter, and sprinkle the raw sugar atop the crust.

Cover pie with foil and cook for another 15-20 minutes until the filling is bubbling.

Allow pie to cool overnight and serve the next day.