Preheat the oven to 350 degrees F.
Place the rhubarb and strawberries in a 10-inch, ovenproof, round skillet (I like cast iron; a 10-inch pie plate or 9-inch square baking dish would also work well), and toss the fruit with the 1/3 cup sugar and 1 tablespoon cornstarch. If you prefer a sweeter dessert or your strawberries are not especially sweet, you may add one extra tablespoon of sugar.
In a mixing bowl, mix the oats, almond flour, almonds, 1/2 cup sugar, and ginger. Add the egg whites and butter, and stir until blended.
Spread the oat mixture evenly over the fruit mixture, leaving a small gap between the topping and the side of the skillet.
Bake for 35-40 minutes or until the rhubarb is bubbling and the topping is crisp and lightly golden. Allow the cobbler to rest for 5 minutes or so. Enjoy hot or at room temperature, with a dollop of whipped cream, vanilla ice cream, or frozen yogurt, if desired.