Preheat the oven to 350 degrees F. Combine the first 5 ingredients in bowl; spoon into an 8 by 8-inch pan. Let fruit macerate 30 minutes. In another bowl, mix together the flour, 1/3 cup sugar, baking powder and salt. Stir in the milk until just incorporated. Spoon the batter over the strawberry/rhubarb mixture; bake 45-50 minutes, or until toothpick inserted in the centre comes out clean. Serve warm or at room temperature.