Tips and notes
1 if you want enrich the texture of the mashed potato, you can increase the butter to 3-4 tbsp, and 150-200ml of milk.
2 Cream will make the mashed potato more smooth and rich. But it is also too heavy to eat. So it is recommend to use full fat milk instead.
3 You can use evaporated milk too. Or half milk half cream.
4 You can replace the milk with water, but the texture won't be smooth