In a large mixing bowl, stir together flour, the 1/3 cup sugar, baking powder, baking soda and salt; set aside.
In a medium bowl, stir together yogurt, banana, oil, lemon peel and vanilla; set aside.
In a small mixer bowl, beat egg whites until soft peaks form.
Gradually add remaining 3/4 cup sugar; beat on high speed until stiff peaks form.
Stir yogurt-banana mixture into flour mixture until moistened.
Fold in about a fourth of the egg-white mixture to soften; then fold in remaining egg whites.
Preheat oven to 350°F.
Pour the batter evenly into a greased and floured 9 by 9 by 2-inch baking pan.
Bake for 40 to 45 minutes, or until a wooden toothpick inserted in the center comes out clean.
Cool cake in the pan on a wire rack for 10 minutes.
Remove cake from pan and cool completely on the wire rack place cake in a storage container or wrap with plastic wrap and store; this cake slices better when held overnight.
For icing, stir together corn syrup and water; add cocoa powder, stirring till smooth.
Drizzle chocolate over cake in a Lacy design.
Let stand about 30 minutes, until set.
Serve with raspberries.
“This was good. I made it for my MIL’s 61st Birthday. I added melted chocolate morsels to the topping because I thought it was too bitter. My only beef is that it seems to dry out quickly. But, other than that everyone liked it very much. I made this for My 3 Chefs Nov 2008”