Serve this side dish with our Poached Salmon with Beet Relish and Green Beans with Tapenade Dressing.
Place potatoes in a medium saucepan filled with cold water and 1 teaspoon salt. Bring to a boil, reduce to simmer, and cook until potatoes are tender when pierced with a fork, 12 to 15 minutes. Drain, and let cool at room temperature.
Prepare mint mayonnaise: Place egg, mustard, lemon juice, and remaining 1/2 teaspoon salt in the jar of a blender; pulse until well combined. With blender running, pour in the oil in a slow, steady stream. The egg mixture will become thick and creamy. Pulse in mint until just combined. Season to taste with salt and pepper. Serve mayonnaise immediately with potatoes, or keep refrigerated up to 3 days.
Raw eggs should not be used in food prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.