How to Bake a Chocolate Cake

AUNT LAUREN’S CHOCOLATE FUDGE CAKE
3 squares of unsweetened chocolate ( or 9 tablespoons unsweetened cocoa plus 3 tblsp. butter)
  
2 1/4 cup sifted cake flour                             2 1/4 cup light brown sugar                                                                                   
2 tsp. baking soda                 [...]