1
: Sift dry ingredients together; set aside.
: Mix wet ingredients :
2
: With electric mixer, cream butter and both sugars. Add eggs, one at a time, beating well after each addition. Add remaining wet ingredients in order, beating well after each addition.
3
: With electric mixer on low speed, fold dry ingredients into wet ingredients beating just until smooth.
4
: In separate bowl, rub all topping ingredients together until crumbly.
5
: Pour batter into one 13" x 9" (33 cm x 23 cm) rectangular or two 8" (20 cm) square baking pans lined with parchment paper. Sprinkle topping evenly over batter. Bake until toothpick in center comes out clean, about 30-35 minutes (do not overbake). Cool completely in pan on wire rack.