Choco-Vanilla Marble Cupcakes for my valentines

This is my 301st post and time to start the journey for another milestone. Hopefully I'll reach there with plenty of awesome recipes, learning and sharing my experience with you all.
These cute looking marbled cupcakes I've made yesterday for my 3 little valentines, my heart and soul, my energy, my love - my 3kids. I have a daughter, who is a chocoholic and twin boys-one of them just loves chocolate and other one doesn't love chocolate at all. He won't eat anything chocolaty, his cupcake has to be white and plain vanilla flavoured. So, I thought why not I combine the two, chocolate and vanilla and try. And as I thought, he loved it and was quite thrilled seeing at the cupcake with two together. Most of the kids love chocolate and what a joy to see them happily eating what their mom made, there is nothing happier for me than this in this World. They are my true Valentine.

These cupcakes are butterless but with eggs. No heavy cream used in here unlike most of the chocolate cake recipe, so it's healthy and filling and great for their evening snack or for school lunch-box. So, let's move on to the recipe.......

You Need :
All-purpose flour(maida) : 11/2 cups
Plain yoghurt(dahi) : 1/2 cup
Canola oil/vegetable oil : 1/3 cup
Eggs : 2
Baking Powder : 1/2 tsp.
Baking Soda : 1/4 tsp.
Salt : a small pinch
Sugar : 1 cup, granulated
Milk : as needed to make a smooth batter(if needed)
Cocoa Powder : 1/3 cup
Vanilla extract : 1 tsp.

How To :

Preheat oven to 175 deC/350 deF. Line your muffin pan with cupcake liners or grease each muffin pan well and dust with some flour. Dust off extra flour from the muffin tin.
In a bowl, mix flour, baking powder, baking soda and salt well and keep aside. In another large mixing bowl, beat oil and sugar well until sugar is well blended. Then add eggs one at a time and beat. Add in vanilla and mix. In there now add flour mixture and yoghurt alternatively until all flour mixture is used.[Yoghurt gives a super soft texture to the cupcakes]
During this process, if you feel the batter is getting dry, add milk just as much as to make a smooth creamy batter. Beat the batter for 3-4 minutes in medium speed. Then divide teh batter in eual two portions. Keep one as it is and in another pne, add cocoa powder and just mix well with the batter with a spoon. Now your batter is ready to go in the muffin tin.
Pour 1 tblsp of white batter first at each muffin tin , then 1 tblsp. of chocolate batter in there, fill each cupcake/muffin tin this way, then with a knife make a swirl in the batter to make the marble effect. Do not fill not more than 2/3 of cupcake mould, I made a mistake filling them almost to the rim, that's why it rose up during baking and cracked. You have to keep some space to let them rise.
Put the prepared muffin tin in the oven and bake for 30-35 minutes or until a toothpick inserted in the middle, comes out completely clean. Remove from pan to cool completely on rack.