1. Prepare the Pie Crust:

• If you’re making a homemade crust: In a large bowl, combine the flour and salt. Cut in the cold butter using a pastry cutter or your hands until the mixture resembles coarse crumbs. Gradually add ice water, 1 tablespoon at a time, and mix until the dough comes together. Shape it into a disc, wrap in plastic, and refrigerate for 30 minutes.
• Preheat the oven to 350°F (175°C). Roll out your pie crust and fit it into a 9-inch pie pan. Trim the edges and crimp them. Line the crust with parchment paper and fill it with pie weights or dried beans. Bake for 10-12 minutes until the edges are lightly golden. Remove from the oven and set aside to cool slightly. If you’re using a pre-made crust, skip this step and proceed directly to preparing the filling.

2. Prepare the Rhubarb Filling:

• In a medium-sized bowl, combine the chopped rhubarb and 1/4 cup of sugar. Let it sit for about 10 minutes to release some of the juices.
• In another bowl, whisk together the remaining 1 cup of sugar, eggs, sour cream, flour, vanilla extract, and cinnamon (if using) until smooth.

3. Assemble the Pie:

• After the rhubarb has released some juice, drain the liquid and stir the rhubarb into the sour cream mixture.
• Pour the rhubarb-sour cream mixture into the prepared pie crust.
• Dot the top with small pieces of butter.

4. Bake the Pie:

• Bake the pie in the preheated oven for 40-45 minutes or until the filling is set and the top is lightly browned. You may need to cover the edges of the pie crust with foil during the last 10 minutes to prevent over-browning.
• The pie should jiggle slightly in the center when done.

5. Cool and Serve:

• Allow the pie to cool to room temperature before slicing and serving. It can also be refrigerated for a few hours to fully set.
• Serve on its own or with a dollop of whipped cream or vanilla ice cream.