Preheat the oven to 180 degrees Celsius (356 degrees Fahrenheit).
Place the bacon in a pan and fry it until crispy.
Meanwhile, put flour, salt, pepper, and oil in a bowl and mix until the consistency resembles a paste.
Add the eggs one at a time, stirring until you have a smooth batter.
Grate onion and zucchini into the batter and fold everything together.
Crumble feta into the batter and cut the crispy bacon into smaller pieces. Add the bacon to the batter and stir, so the feta and bacon are evenly distributed.
Pour the batter into a greased springform or tart pan and sprinkle with grated cheese.
Place the zucchini tart in the lower part of the oven and bake for about 35 minutes at 180 degrees Celsius (356 degrees Fahrenheit).
Remove the finished tart from the oven and let it cool briefly before serving.
Release the tart from the pan and serve with freshly baked bread and a light salad.
The tart also works perfectly as a cold dish for a buffet.