Preheat oven to 350 degrees
Mix flour, baking powder, and lemon zest in a bowl.
In a separate bowl beat olive oil, yogurt and sugar for 10 minutes
Beat egg yolks in a separate small bowl
Add egg yolks to oil mixture, folding in until the mixture is smooth. Add flour and mix well by hand.
Brush baking dish with olive oil. Add cake batter and bake for 1 hour.
Brush cake with melted butter, honey, and balsamic mixture.
Sprinkle salt onto chopped garlic. Mash into puree with blade of knife held sideways. Scrape into medium bowl.
Scrape out and discard cucumber seeds. Coarsely grate cucumber.
Squeeze grated cucumber firmly to extract as much juice as possible. Discard juice. Add to bowl with garlic.
Add yogurt, balsamic, olive oil, dill and pepper, stirring together well.
Cover and refrigerate for at least 2 hours for flavors to blend. Add more salt if needed.