Seasonal Galette with Pistachio Frangipane

1 3/4 cups flour
1/3 cup granulated sugar
1/4 cup yellow cornmeal
1/4 tsp salt
1/2 cup cold butter
cut into small pieces
1/2 cup buttermilk or Crème Fraiche
1 egg
1 tsp heavy cream
2 tsp sugar
1 orange
2 cups fresh strawberries
1 1/2 cups rhubarb
1/2 cup sugar
2 1/2 tbsp quick tapioca
1/8 tsp cardamom
2 oz Butter
room temperature
½ cup Sugar
1 cup Pistachios
Pinch of Salt
Zest of 1 lemon
Preheat the oven to 350 degrees F.
For the Dough
In a large bowl, combine the flour, sugar, cornmeal and salt. Add butter and with a pastry cutter or using your fingers until the mixture resembles coarse meal. Pour the buttermilk into the bowl and stir until the dough begins to stick together and you can gather it into a ball as much as possible.
Roll out in between parchment papers to form a rough circle about 14-in in diameter. Refrigerate for at least 30 minutes.
For the Filling
In a medium bowl, whisk together the sugar, tapioca, cardamom and orange zest. Add the strawberries and rhubarb and toss to completely coat. Let sit for 15 minutes before placing onto the crust so the tapioca has time to rehydrate.
For the frangipane
Grind the pistachios in the food processor to a fine powder. In a kitchen aid with the paddle attachment cream the butter, sugar and lemon zest together until light in color. Add the pistachios and salt, mix just until combined. Add the egg and mix just until incorporated.