Peel the potatoes and cut them in half or to a uniform size. Add the potatoes to a large saucepan of water with the salt. Bring to a boil, then reduce the heat to medium and cook until tender but not falling apart. About 25 minutes.
Drain the potatoes and place the pan back on the lowest heat setting until any remaining water has steamed off and disappeared. The potatoes should look dry and floury.
Add the butter and when it has melted, mash the potatoes.
Heat the cream in the microwave for 30 seconds and add to the potatoes, mash until smooth and creamy.
Add the ricotta cheese and blend until completely incorporated.
Notes
Let the butter melt in the pan of hot potatoes before mashing. Alternatively, you can melt the butter in the microwave and add to the potatoes.
Adding the hot cream will keep the potatoes from lumping.