Combine vinegar, sugar, and salt with ½ cup water in a small saucepan. Bring to a simmer, and whisk until sugar and salt have dissolved.
Add sliced onions to a small mason jar, then pour hot brine over them.
Let sit for 15 minutes, then drain. Return to the mason jar, and refrigerate until ready to use.
Crab Deviled Eggs:
Peel eggs, then slice them in half lengthwise.
Carefully scoop out yolks, and place in a medium mixing bowl.
Transfer cooked egg whites to a serving platter.
Mash yolks with a fork, then stir in the mayonnaise, mustard, fresh dill, Old Bay, salt, and pepper until smooth.
Pat crab meat dry with a paper towel. Use your fingers to feel around the crab meat, removing any small pieces of shells. Fold 2 ½ ounces crab meat (roughly ½ cup, loosely packed) into the egg filling, reserving the rest for topping.
Scrape mixture into a pastry bag fitted with an open star piping tip. Pipe generously into the egg white halves.
Garnish with the remaining crabmeat, pickled onions, more chopped dill, and a sprinkle of Old Bay.
Notes
Storage Tips: Store pickled onions in a mason jar in the refrigerator for up to 5 days. Store leftover deviled eggs in an airtight container in the refrigerator for up to 2 days.Expert Tips: My long-time favorite method for hard boiled eggs is to use Cooks Illustrated’s method. Start by placing eggs in a saucepan and covering them with cold water by at least an inch. Bring them to a hard, rolling boil, then turn off the heat, cover, and let stand for 10 minutes. Use a slotted spoon to transfer them to a bowl of ice water for 5 minutes. Perfect hard-boiled eggs every time!That said, I now have a 7-egg Dash Egg Cooker, and I absolutely love it! It’s now my favorite way to make soft-boiled or hard-boiled eggs. As with the saucepan method, cool your hard-boiled eggs in an ice water bath as soon as they are done. That makes it easier to peel eggs.Don’t have a piping bag? No worries! Scrape the filling into a ziptop bag and cut the corner off. Squeeze the filling out of the whole like it’s a piping bag.