Defrost the cream. My mother moves cream's bowl from the freezer compartment to one of the shelves below the previous night.
Then in the morning, she takes the bowl out of the fridge some 2-3 hours before she plans to make ghee.
Add water to the cream after it reaches room temperature. Mom usually adds about a cupful of water, and then if needed, goes on adding more water gradually while churning. (If the cream is cold, you can use lukewarm water.)
Churn the mixture using a butter churn till butter separates from buttermilk.
Wet your hands, and then scoop out the butter and transfer it to the vessel that you will use to make ghee in. Make sure you use a thick-bottomed vessel otherwise the ghee will get burnt. (I would probably use a non-stick vessel for this but my mother prefers to use a steel vessel.)
Start to heat the butter on low flame.
As the melted butter heats up, the liquid starts to bubble and rise up. To prevent the liquid from spilling out, keep a spatula or a ladle in the vessel.
Initially, you will need to stir the liquid continuously as it bubbles up. After 10-15 minutes, my mother usually transfers the ghee to a fresh vessel to prevent the milk solids from getting stuck to the vessel and causing a burnt taste in the ghee.
After the liquid has clarified enough, it will not rise up. You don't need to stir after the liquid has settled down.
Now watch out for the change in color of ghee. After the ghee has turned golden in color, add a drop or two of water in the mixture. You know your ghee is ready when it makes a crackling sound. (The sound will be similar to the sound made by mustard seeds when added to hot oil.)
Now strain the ghee using a sieve to remove light brown milk solids that form at the bottom of the vessel. These milk solids, which we call beree in Marathi, taste good (sort of like crumbled paneer) when added to sabzis.