Preheat oven to 375ºF
Lightly coat russet potatoes with olive oil and a pinch of salt. Using a fork, poke your potatoes all over and then place them on a baking sheet to bake for 1 hour (or until soft).
Remove potatoes from the oven to cool down for 5 to 10 minutes.
Once slightly cooled, cut off the tops (lengthwise) and scoop out the centers, placing the scooped-out potatoes in a large mixing bowl (a stand mixer bowl is preferred)–be careful not to tear the skins. Set the potato skins aside (do not throw the potato skins out).
To the bowl with the potatoes, add chicken stock, heavy cream, butter, and 1 tsp of salt. Mix well using a masher or a stand mixer fitted with a whisk attachment.