Preheat oven to 350 degrees. Grease and flour an 8 x 8 inch baking pan.
Stir chocolate chips, brown sugar, pecans, olive oil and cinnamon in a small bowl until well mixed, set streusel aside.
In mixing bowl combine dry ingredients, make well in the center. Pour in greek yogurt, olive oil, banana, egg, and flavoring, stir until just blended.
Spread half of batter in prepared pan. Sprinkle with ½ of streusel.
Repeat with remaining batter and streusel.
Bake cake about 45 minutes or until cake tester comes out clean from center.
Cool cake in pan on rack.