Ingredients-
1. All Purpose Flour- 275g
2. Baking Powder- 1 tsp
3. Soft Butter- 115 g
4. Caster/ Powdered Sugar- 60g
5. Condensed Milk- 200 ml
6. Vanilla Extract- 1 tsp
7. Yogurt- 200 ml
8. Vinegar- 1 tbsp
9. Baking Soda- 1/4 tsp
10. Unsweetened Soda- 120 ml

Procedure-
1. Prepare a baking pan.
2. Keep 3 bowls ready.
3. In first bowl, sieve flour and baking powder
4. In second bowl, add butter, sugar, vanilla and condensed milk. Whisk well.
5. Add flour mixture to the butter mixture and mix well.
6. In third bowl, add yogurt and whisk to make it smooth, add baking soda and vinegar. Mix them with a spoon. As soon as it gets bubbly add it to the batter and gently cut and fold.
7. Add soda and fold gently.
8. Bake in a pre heated oven in the middle rack with both Rods and fan on at 170 degree C for 25 mins or until the top is slightly golden and when a skewer inserted comes out clean.
9. After 25 mins, let it remain in the oven with oven turned off for 5 mins.
10. Take it out and let it cool.

Notes-
1. If your oven has hot spots, turn the pan around halfway through the cooking time.
2. If you don’t bake a sheet cake and do an 8″ instead, the cooking time will slightly increase.
3. If you want to do it in a 6″ pan, use two instead of one.
4. Always start with a lower oven temp and set a lesser duration to bake a new recipe than what is given in the recipe (including this one) because everyone’s oven is different.

P.S- there are absolutely no substitutes for this recipe so please don’t ask me if you can substitute any ingredients for another.
If you wish to, then you can do your own experiment and let me know the result.