Eggless Yogurt (Curd) Sponge Cake

When it comes to baking, I try to be precise about measuring ingredients. And follow the tips for making any cake soft and moist. 
Some say any cooking oil makes a cake really moist. My personal experience says Eggless Sour Cream Cake turns soft. Recently, I found out Silken Tofu cakes are soft too. Some day, maybe I'll try that. But sour cream and silken tofu are not the ones easily available. What works best for an egg less cake?  Homemade thick yogurt a.k.a curds with little butter and little oil.

Ingredients:
All Purpose Flour/Maida - 1 1/2 cups
Thick Yogurt/Curd/Dahi - 1 cup
Sugar - 3/4 cup
Unsalted Butter - 1/4 cup
Oil - 1/4 cup
Vanilla Extract - 2 tsp
Orange Zest/Peel - 1 1/2 tsp
Baking Powder - 1 tsp
Baking Soda - 1/2 tsp
Salt - 1/4 tsp

How to bake an Egg less Yogurt Sponge Cake:

• In a small mixing bowl, add the dry ingredients - all purpose flour, baking powder, baking soda and salt.  Mix well.
• Preheat the oven at 350 degrees F. Grease a loaf pan with cooking spray or oil.

• In another big mixing bowl, add yogurt, softened butter, oil, orange zest, vanilla extract and sugar. Mix well with a whisk until sugar dissolves.
• I have used thick whole milk / full fat yogurt for this cake. Thicker the yogurt, softer the cake. Greek yogurt or hung curds would be good too.
• If you like your cake more sweet, add 1 - 2 tbsp more sugar.
• Now add the dry ingredients, little at a time to the big bowl. Mix well with a spatula, until you get a smooth and thick cake batter. Pour this batter in the greased pan. Bake for about 35 - 40 minutes or until a toothpick inserted in the center of the cake comes out clean.

Let the cake cool in the pan for about 5 minutes. Invert the cake pan on a cooling rack and lightly tap the pan. Slice the cake after it cools down completely.