12 oz red-skinned potatoes, cubed
1/4 cup sliced scallions
3 Tbsp sour cream
2 Tbsp unsalted butter
1 tsp dijon mustard
Salt and white pepper to taste
Cook potatoes in a pot of boiling water until fork tender, 10-12 minutes, drain. Return potatoes to the pot and cook over medium heat, stirring, to remove excess moisture, 1 minute.
Add scallions, sour cream, butter, and dijon, smash potatoes with potato masher until desired consistency. Season potatoes with salt and pepper.