1-1/4 to 1-1/2teaspoonsDijon mustard, to taste (I use Maille or Fallot)
a few dashes of hot sauce, to taste (optional)
kosher salt and freshly-ground black pepper
paprika and/or chopped herbs (like dill or chives), for garnish
Place eggs in a heavy-bottomed pot and cover with cool water by 1 to 2 inches. Vent lid and bring just to a boil. Cover pot completely, lower heat, and simmer for 30 seconds. Remove from heat and let stand, covered, 12 minutes. Transfer eggs to a bowl of ice water and let stand for 10 minutes before peeling under cold running water.
Slice eggs in half lengthwise. Gently separate the egg yolks from the whites and place the yolks in a bowl.
Use a small whisk to mash the egg yolks with mayonnaise, sour cream, and Dijon mustard until smooth. For a very smooth and creamy filling, use a use a hand mixer (my preferred method). Season to taste with hot sauce (if using), salt, and pepper.
Using a spoon, a pastry bag fitted with a star or plain tip, or a zip-top plastic bag with one bottom corner snipped off, fill each egg with some of the yolk mixture. Sprinkle each egg with a pinch of paprika and/or chopped fresh herbs. (See the blog post above for additional garnish ideas.)
For more tips and techniques, don't miss myUltimate Guide to Deviled Eggs.If you prefer more acidity in your Deviled Eggs, you can add a little white wine vinegar or lemon juice. Taste the filling first, and start with 1/4 teaspoon vinegar or juice. The Dijon mustard does lend tang to the recipe, so it's best to start conservatively with any additions, and build, to taste.
You can boil the eggs and make the filling up to two days in advance of serving. Refrigerate the whites and filling separately in airtight containers, and fill and garnish the day of your party.