1
: In large bowl, whisk eggs and sugar together. Add remaining wet batter ingredients in order, stirring well after each addition.
2
: In separate bowl, sift dry ingredients together.
3
: Stir dry ingredients into wet ingredients just until mixed. Stir in additions, if desired.
4
: Pour into parchment-paper lined 9" (23 cm) non-stick square pan and bake in preheated 350°F (180°C) oven for 25-30 minutes or until toothpick inserted in center is almost dry. Cool completely on wire rack. Dust with icing sugar, if desired.
5
: Cut into bars just before serving. Store tightly covered at room temperature.