Blueberry Rhubarb Crisp

The poppies are in bloom and the farmer's markets are filled with piles of fresh rhubarb. Time for a recipe!

The common combination of rhubarb and strawberries is nice, but this recipe uses blueberries in place of the strawberries and I think it is even better. I'm not remembering where I got this recipe. I think that it might be from Bon Appetit a number of years ago.

Filling
2/3 cup sugar
4 Tbl. flour
2 lb.  rhubarb cut into 1/2" pieces
4 cups blueberries - about 22 oz.

Topping
2/3 cup pistachios - finely chopped
1 1/2 cup flour
1 cup sugar
1/2 cup brown sugar
1 1/2 sticks cold butter

1. Preheat oven to 350 and butter 13x9 glass baking dish
2. Combine sugar and flour in bowl and add cut up rhubarb and blueberries. Toss to coat and put in baking dish.
3. To make the topping - whisk together the flour and sugars. Cut the butter into 1/2 inch cubes and with fingers or pastry blender, blend it into flour mixture until it clumps together and then add the pistachios and mix well.
4. Squeeze the topping mixture together into clumps and put on top of the fruit.
5. Bake until filling is bubbling and topping is crisp - about 50 minutes.

Serve warm or at room temperature.