1. Preheat the oven to 350°. Generously butter an 8-inch square baking dish. In a large mixing bowl, combine the rhubarb and strawberries and toss to mix. Sprinkle on the tapioca, brown sugar, and ¼ cup of the flour. Stir gently and transfer to the prepared baking dish.

2. In a separate bowl, combine the remaining cup flour, the granulated sugar, cinnamon, baking powder, and salt. Whisk to blend thoroughly. Pour on the melted butter and toss with a fork to create a crumbly mixture. Scatter over the rhubarb and bake for 45 minutes to 1 hour or until the rhubarb is tender when pierced and the crust is lightly browned.