Savory Zucchini Sandwich Cake

Light and fluffy savory zucchini cake that doubles as a sandwich
Source: My mom

Taste: 4 (out of 5)
Difficulty: 2 (out of 5)

Ingredients:
For the batter
- 200 g mayonnaise
- 200 g sour cream
- 3 eggs
- 160 g all purpose flour
- 1 tsp baking powder
For the filling:
- 1 tbsp oil
- 1 medium onion
- 2 garlic cloves
- 2 medium zucchinis
- 1 tsp salt
- 1/2 tsp black pepper
- 1 egg
Total: 9x9 inch square cake, 8 servings, 390 cal / serving

Directions:
For the filling:
1. Peel the onion and the garlic and finely chop in a food processor.
2. Preheat oil on medium heat in a frying pan and saute the chopped onion and garlic for 5-7 minutes, stirring.
3. In the meantime, finely chop the zucchini in the food processor. Add to the onion, season with salt and pepper and saute for another 5-7 minutes, stirring.
4. Let cool to room temperature, add the raw egg and mix well.
For the batter:
5. Preheat oven to 350F (375F in my oven) and grease a 9x9 inch square baking pan.
6. Mix all the batter ingredient using a mixer, you should it should be the consistency of sour cream.
7. Pour half of the batter into the pan and bake for 10-12 minutes.
8. Remove from the oven, spread the filling evenly over the baked part, and pour the remaining batter over the filling.
9. Return to the oven, bake for 20 minutes at 350F, then reduce to 250F (275F in my oven), cover with aluminum foil (to prevent the top from burning) and bake for another 20 minutes.
10. Serve slightly warm or cold.

Afterthoughts:
- The batter is very fluffy and light, almost like an omelette.
- This cake can be served as a main dish or as a side instead of bread.
- You can try many other variations of the filling: cabbage, tuna, cheese.