First of all beat eggs, sugar, together make it fluffy foamy

Then add oil, butter again beat it

Then add yogurt, vanilla essence, lemon zest and beat all together

Put wet ingredients separate now in separate bowl add flour, baking powder

Now add dry ingredients into wet ingredients and fold it with the help of spatula don't beat it otherwise it will not rise and fluffy

Fold it with light hands until all mixture combine together make sure there should be no lumps

Now if you want to make brown ones separate half mixture add 1 tbspn of cocoa powder mix it brown batter is ready

Now preheat the oven and bake it for 18 to 20 minutes in 180°c

Put papercup moulds into cupcake tray and pour the batter and sprinkle some chocolate chips on top before baking