Whisk butter and sugar together until creamy and double in volume.
Use electric hand blender with a whisk attachment for the purpose.
Now add yogurt and whisk the batter for 3 - 5 minutes at medium speed.
Add the oil and vanilla essence. Continue whisking the batter for 5 minutes.
Next, add the buttermilk and coffee paste. Whisk the batter for 5 minutes.