Preheat oven to 375° F, Spray a 9 inch or 8 inch baking dish with non-stick cooking spray. Place prepared baking dish on a cookies sheet lined with foil to catch any drips or bubbling from the grunt.

Combine the rhubarb and the strawberries with the sugar, cornstarch, and salt in a bowl. Let sit for 10 minutes, and transfer to your prepared baking dish on the cookie sheet.

Meanwhile make the biscuit topping. Whisk together flour, sugar, baking powder, pinch of salt, in a medium bowl. Stir together milk and butter in another small bowl. Stir milk-butter mixture into flour mixture. Drop heaping spoonfuls of biscuit batter on top of filling, spread the better around with your fingertips, batter will be sticky.

Bake for 45 minutes or until the fruit filling is thickened and bubbly, and the biscuit topping is golden.