Mom's Famous Half-Shell Potatoes

My mother's simple recipe for twice-baked potatoes. I've experimented using sour cream in the filling and cooked crumbled bacon, slivered green onions and even crab or baby shrimp for topping before baking -- but I still like her original recipe best.

• Ready In: 1 hr 50 mins
• Serves: 6

Ingredients

• FOR PRE-BAKING

•  vegetable oil, to coat potatoes before baking
•  kosher salt, to sprinkle on potatoes before baking
•  aluminum foil, to wrap potatoes before baking

• POTATOES

• 6  medium russet potatoes
• 2  tablespoons salted butter
• 2  tablespoons  real mayonnaise
• 1⁄3 cup  whole milk
• 2  tablespoons  finely chopped  vidalia onions
• 1⁄2 cup  shredded sharp cheddar cheese (for filling)
•  kosher salt, to taste
•  finely ground pepper, to taste

• TOPPING

• 1 1⁄2 cups sharp cheddar cheese (for topping)
•  paprika (for garnish)

Directions

1. PREHEAT oven to 400°F with rack in the center position.
2. WASH the freshest smooth-skinned blemish-free russet potatoes; PIERCE each potato evenly 4 times using a fork; COAT each potato with vegetable oil; SPRINKLE each potato lightly with kosher salt; WRAP each potato with aluminum foil.
3. PLACE potatoes on center rack in oven; BAKE potatoes for 1 hour.
4. REMOVE potatoes from oven; ALLOW to cool just slightly; LOWER oven temperature to 350°F.
5. REMOVE foil from one potato at a time with one oven mitt; CUT potato lengthwise on a cutting board with a serrated knife across the flattest, widest surface; HOLD hot potato in oven mitt; SCOOP put out potato pulp carefully from each half into a large bowl, leaving enough skin and pulp in each shell to support filling; PLACE each shell cut-side up on a cookie sheet; REPEAT same process with remaining potatoes, working quickly and carefully while potatoes are still warm.
6. WHIP potato pulp well using a potato masher or fork; ADD 2 tablespoons softened butter, 2 tablespoons real mayonnaise, 1/3 cup whole milk, kosher salt and finely ground pepper to taste (more milk may be added for potatoes to remain stiff yet fluffy; ADJUST seasoning if needed; STIR in 1/2 cup shredded sharp cheddar cheese; FOLD in chopped onion last, just until combined.
7. FILL each potato shell on the baking sheet evenly until all of the potato mixture is used; TOP each potato with sharp cheddar cheese, divided evenly between potatoes; SPRINKLE potatoes lightly with paprika (smoked paprika is good); potatoes may be covered and refrigerated up to 24 hours before baking.
8. BAKE potatoes on the center rack in oven, for 15 minutes.
9. COOL baked potatoes for 3-5 minutes.
10. SERVE and enjoy!