Bring a large pot of water to a boil. Add the chicken and simmer until cooked through, approximately 10 minutes. Drain, cool and cut into cubes.
While boiling chicken, make the mayonnaise: Using a blender or hand held electric mixer, beat the egg, mustard, salt, water and vinegar until light and frothy.
Add the oil a tablespoon at a time, beating thoroughly after each addition.
Once mixture begins to thicken, you can add oil more quickly.
Continue until mixture reaches the consistency of creamy mayonnaise.
NOTE: The more oil you add, the thicker it gets; you may not need the full cup of oil.
In a large bowl, toss together the chicken, grapes, pecans, blue cheese and 1 cup of the mayonnaise. Stir until evenly coated, adding more mayonnaise if necessary. Refrigerate until serving.
Elegant Brunch Chicken Salad · Dinner Match Lab | Dinner Match Lab