1 egg (room temperature)
1 tsp. salt
1 tsp. prepared mustard
1 tbsp. cider vinegar
Oil
1/4 to 1/2 c. skim or whole milk

Put 1 egg, salt and mustard into blender, pour cider vinegar into a 8 ounce measuring cup; add oil to the top. Start blender, slowly add oil and vinegar. When mixture has thickened to mayonnaise consistency add just enough milk (keep blender going) to keep it thick.