Heat the oven to 425 F. Spray baking sheet with cooking spray.
In a large mixing bowl, re-sift the flours, baking powder and sugar together. Using a fork, cut the chilled margarine into the dry ingredients until the mixture resembles coarse crumbs. Add the chilled milk and stir just until a moist dough forms.
Turn the dough onto a generously floured work surface and, with floured hands, knead gently 6 to 8 times until the dough is smooth and manageable. Using a rolling pin, roll the dough into a rectangle 1/4-inch thick. Cut into 8 squares. Place the squares into the prepared baking sheet and bake until golden, 10 to 12 minutes.
Transfer the biscuits onto individual plates. Top each with 3/4 cup strawberries and 1 1/2 tablespoons yogurt. Serve immediately.