Preheat oven to 375 degrees. Grease a 13-by-9 baking dish.

Combine the topping ingredients in a small bowl, pressing with a fork or pastry blender to combine.

In a medium bowl, mix together the flour, baking powder and salt.

In a large mixing bowl, cream the sugar and shortening with an electric mixer—the result will be a bit clumpy. Add egg, mix to combine. Alternately mix in flour mixture and milk in batches, beginning and ending with flour, scraping down the side of the bowl occasionally, and mixing until smooth.

With a spoon, gently fold in the blueberries. The batter will be very dense, so go easy on the berries! Spread into the greased dish. Crumble topping over the surface of the cake and bake 45-50 minutes or until a toothpick comes out clean.

Once cool, cut into squares and serve. I usually get 10 big slices for dessert, or you could cut it into 12 or 15 for smaller, afternoon-coffee-size snacks.