3 egg yolks, room temperature
1 tbsp. Dijon mustard
1 tbsp. wine vinegar or cider vinegar
1/2 c. light olive oil
1 c. vegetable oil
Salt and pepper
2/3 c. fresh dill, minced
6 lbs. new potatoes, boiled, peeled & diced
2/3 c. sweet red onion, finely chopped
Fresh dill sprigs (optional garnish)

Combine yolks, mustard and vinegar in processor or blender and mix until thick and smooth, about 2 minutes. With machine running, gradually add oils through feed tube in slow steady stream, stopping machine occasionally to be sure oil is being absorbed (add 2 tablespoons very hot water if mixture begins to separate), until mayonnaise is very thick. Season with salt and pepper. Transfer to a large container and blend in dill. Gently fold in potatoes and onion, coating well. Refrigerate overnight. Garnish with fresh dill sprigs.