Preheat the oven to 375F and take out a 9 inch pie plate.
Combine the rhubarb and strawberries in a large pot over medium heat.
In a separate bowl, stir the brown sugar, cornstarch and salt together then add to the fruit.
Add the zest, juice and vanilla paste.
Cook until the mixture is boiling and the liquid has thickened, about 15-20 minutes.
Set aside to cool slightly while you make the crust.
In a large bowl, combine crust ingredients and mix gently with a spoon or spatula until crust just comes together, about 30 seconds. If dough isn't sticking together and seems dry, add in more ice water 1 tbsp at a time. I highly recommend watching the YouTube video to see how the dough is supposed to look.
Turn dough out onto lightly flowered surface and knead once or twice so that the the ball of dough is mostly sticking together. Take care not to knead more than a few times as you could overwork the dough. If it isn't sticking together 100%, that's ok. It'll come together when you roll it out.
Divide the dough into two balls, one slightly bigger than the other.
Roll out the larger ball of dough taking care to use lots of flour for your counter while rolling. The dough is a bit crumbly and sticky. It may break apart a bit but that’s ok. It’s supposed to be rustic.
Roll the dough to be a bit bigger than the pie dish.
Transfer the dough to the pie dish. I like to roll it up onto the rolling pin to help with the transfer process. Use a bench scraper to help you. It’s ok if the dough breaks, just press it back together in the dish.
Scoop the pie filling into the pie dish.
Roll out the top crust the same as the bottom crust and transfer overtop of the pie.
Roughly pinch together the edges of the pie crust. I like to tuck it in the edges instead of trimming them for maximum crust-age.
Brush the top of the pie with the heavy cream and sprinkle with the raw sugar.
Cut 3 slits into the pie to release steam.
Place the pie onto a large baking sheet and bake for about 45 minutes or until golden brown.
Let cool completely before slicing and serving with vanilla ice cream.