In a pan, heat butter and add flour. Cook the flour on low heat for 45 seconds.
Add milk to the pan, while whisking continuously till there are no lumps. Bring this to a boil while stirring continuously. This avoids lumps in the sauce. Reduce the heat once the sauce comes to a boil.
Stir in parsley, salt, pepper, cheese and the potatoes. Add more milk if the sauce is too thick. Cook for 2-3 minutes and switch off the flame. Sprinkle with more parsley and serve hot.
Notes
Note 1: I like to keep the skin on the baby potatoes but you can choose to remove it if you like. You can also substitute baby potatoes with regular potatoes and quarter it before adding it to the sauce. Make sure to add properly cooked potatoes to the sauce.To cook potatoes, boil them in salted water. They are cooked once a fork can be inserted in them without any resistance.