Take a bowl, add oil / butter, dahi,sugar, salt, mix well..
Take a kadai, add salt, put a stand, cover a lid, preheat for 10 minutes.
Take cake tin of any shape, grease thoroughly with oil, put a butter paper, apply oil evenly.
Meanwhile take a bowl, put a strainer on bowl, add maida, cocoa powder, eno soda, strain it, add milk, vanilla essence, mix well.
Batter should be in pouring consistency. Now pour in tin, tap 2 3 times to remove air bubbles.
Keep tin in preheated kadai, cover lid. On a slow to medium flame, bake a cake at least for 30 to 40 minutes, time may be differ, so check after 30 minutes, prick a toothpick in a middle of cake, if it comes out clean, then cake is perfectly baked, or not then bake more for 5 to 10 minutes.
Take out from kadai, keep aside to cool completely for at least 1 hour.
Take a bowl, add instant coffee powder, sugar powder, hot water. Beat with the help of electric beater or hand beater for at least 10 minutes or till it's colour changes and peak fluffy. Dalgona coffee cream is ready. Keep it in fridge till cake cools completely.
Now unmould cake from tin, divide it in horizontally. Apply dalgona coffee cream evenly, put other half part of cake on it, press gently.
Now apply on dalgona coffee cream on evenly on upper side and all around cake.
For garnishing, sprinkle coffee powder on cake, put chocolates flowers on it..