Preheat oven to 350°F. Butter and flour one 8x8x2 cake pan.
Sift flour and baking powder together and set aside
Beat egg whites until stiff peaks form. Set aside
In a large bowl whisk together sugar, egg yolks, cheese, and milk. Slowly, whisk in melted butter. Stir in flour mixture until completely blended. Carefully, fold egg whites into the mixture until incorporated and smooth.
Pour into prepared pan. Sprinkle sesame seeds over the top of the batter.
Bake for 40-45 minutes or golden brown. Remove from oven and allow to cool for 10 minutes. Cut into 16 even pieces. Serve warm.
Additional tip: If necessary, finely grated Parmesan cheese can be substituted.