Preheat the oven to 375°. Spray an 8×8 baking pan with cooking spray and set aside.

In a medium bowl, combine flour, sugar, baking powder and salt. Cut the shortening into 4 to 6 chunks and scatter across the top of the dry ingredients. With an electric mixer on low speed, cut in the shortening until the mixture looks like coarse sand (a few small lumps are fine).

Combine the milk, vanilla and egg in a bowl or measuring cup and add all at once to the flour mixture. With the mixer, beat at medium speed until well blended, scraping down the sides with a rubber spatula if needed.

Pour the batter into the prepared pan and smooth the top. Bake for about 30 minutes or until the top is golden and springs back when lightly touched, and the cake has pulled slightly away from the edges of the pan.

Let cool at least 10 minutes before serving. Store leftovers at room temperature if using within a day or two; refrigerate if storing longer. Reheat leftovers in the microwave about 30 seconds on medium before serving.