1. Gather all ingredients and equipment needed.
To Make Mashed Potatoes:
2. Rinse potatoes, peel, and dice into cubes, and hold in cold water.
3. In a large pot, add cold water and potatoes, turn on the heat and bring to a boil then reduce to a simmer and cook for about 20-25 minutes until potatoes are fork tender.
4. Drain potatoes, place in a large bowl, cool slightly and mash potatoes, add in melted butter, salt, and black pepper. Mix until fluffy and fully incorporated.
To Make Choux Paste:
5. In a medium saucepan or pot combine milk, butter, sugar, and salt.
6. Turn on the heat to high and cook liquids until the butter is fully melted and is just at a boil. Then remove from heat and add flour. Using a wooden spoon, mix until there are no more lumps.
7. Then return to stove top at medium heat and cook, while continuously stirring till the dough gets to 175° (80°C) or until a thin starchy film forms all over the bottom of the pan or pot as the dough comes together as a ball. Transfer dough to a stand mixer bowl.
8. Attach stand mixer bowl to the stand mixer and fit with a paddle attachment and turn on to medium speed. Beat dough until dough reaches 145° (62.8°C) or until cool enough that eggs don’t cook when they hit the dough.
9. Add the eggs one at a time until fully incorporated. Scraping mixer in between until it forms into a shiny paste.
To Make Pommes Dauphin:
1. In a large bowl, mix mashed potatoes and choux paste until fully incorporated.
2. In a large pot, add oil for frying and heat to 340°F (171°C). Using a 1oz scoop, scoop dough and carefully drop it into hot oil and deep fry for 3 ½ minutes until all sides are light golden brown. Then using a slotted spoon or skimmer, spoon out the deep-fried dough and transfer it to a serving dish. Repeat the steps until the dough is finished. Serve immediately.