1tablespooncream cheese(heaping tablespoon) at room temperature
In a microwave-safe mug, add all the dry ingrdeints. Whisk with a fork and mix well.
Add all the wet ingredients to the dry mix. Make a lump-free batter. (ref note4)
Microwave for 90 seconds at full power. (ref note 5)
Let the mug cake cool down a bit.
While the cake is cooling down, whisk cream cheese, heavy cream, and sugar until light and fluffy.
Once the cake has cooled down a bit top it with cream cheese frosting.
If you don't have buttermilk, to ¼ cup of milk add ¾ teaspoon of vinegar. Let it sit for 5-8 mins. The milk will curdle.
For a vegan version, replace butter with oil.
The amount of food colour depends on the type. If you are using gel colour a very small quantity would be enough. In the case of liquid food colour, you would need about ⅛ teaspoon.
Make sure the cup is only half-filled with the batter, else it might spill while baking. If you don't have a big enough cup, divide the batter into two cups.
Every microwave is different. Cook it in Microwave mode. After 1 minute check the mug, if you see the batter is pulled away from the sides and top looks firm, then it is done. Else bake for 10-15 seconds more.