Preheat the oven to 350 degrees F. Spray or grease the bottom of an 8-by-8-by-2-inch pan.
Melt the chocolate with the shortening in the microwave or over a double boiler. Cool slightly. In a mixing bowl, beat the eggs well. Add the sugar and combine thoroughly, then stir the chocolate mixture.
Sift the flour together with the baking powder and salt, and stir into the flour mixture. Stir in the pecans and vanilla extract.
Spread the batter evenly in the prepared pan. Bake until a toothpick inserted in the center comes out clean, 25 to 30 minutes. Cool in pan for 5 minutes and cut into squares. These are delicious warm or cold. Spread with Coconut Frosting.
Combine the evaporated milk, sugar and egg yolks in a saucepan. Stir with a wire whisk until the yolks are fully incorporated. Add the butter, melt, and bring to a simmer. Cook until the mixture thickens, 12 to 15 minutes, stirring constantly. Add the coconut, nuts and vanilla extract and let cool.
Recipe adapted from Georgia Cooking in an Oklahoma Kitchen by Trisha Yearwood (c) Clarkson Potter 2008