Preheat the oven to 400° F and line a baking sheet with parchment paper.
In a large bowl, combine one cup of Bisquick, one-quarter cup of vegetable oil, and two tablespoons of milk.
Mix with a fork until the mixture forms a ball. Shape dough into a disk and wrap it in plastic. Refrigerate for at least one hour.
In a separate bowl, combine one cup of rhubarb, one cup of raspberries, one-half cup of sugar, and two tablespoons of quick-cooking tapioca; let stand for 15 minutes.
Take the dough out of the refrigerator, unwrap it and place it on the prepared parchment-lined baking sheet. Roll the dough into a circle.
Spoon the fruit mixture into the center of the dough, leaving room at the edges. Fold the edges of the dough over the fruit. Leave the center uncovered.
Bake for thirty minutes or until the crust is golden brown, and the filling is bubbly.
Combine the glaze ingredients in a small bowl and drizzle it over the warm tart.
Serve and enjoy!