Preheat oven to 450 degrees. Lightly spray or grease an 8 x 8-inch pan.
Beat eggs in a bowl; add oil and beat Add polenta, flour, baking powder and salt; mix. Add grated zucchini, water, yogurt, cottage cheese and sour cream. Add salt to taste now or later at the table. It should be a somewhat thick batter, but if too thick, add more water.
Pour into pan so that it's about 2 or 3 inches deep. An 8x8-inch pan worked for me. Lower oven temp to 350 and bake for 35-40 minutes.
Remove from oven when it is cooked (toothpick should come out relatively clean when inserted 3/4 of way to middle of pan). While warm, use a knife to slice into diamond shapes while still in the pan.
Mix together all the topping ingredients, and pour evenly over the baked base so it will soak through. Return to oven for another 10 minutes. Topping should be somewhat set. Remove from oven, and leave to sit for about 10 minutes. Residual heat further cooks the topping.