• For onion relish
  • 2 yellow onions , thinly sliced
  • 1/4 cup dark brown sugar
  • 1/2 cup red wine vinegar
  • 1/2 cup balsamic vinegar
  • For aioli
  • 1 egg yolk
  • 1/2 garlic clove , minced (about 1/2 teaspoon)
  • 1 teaspoon Dijon mustard
  • 1/2 ounce white wine vinegar
  • 4 ounces grapeseed oil
  • 1 ounce olive oil
  • 1/4 teaspoon kosher salt
  • 1/8 teaspoon fresh ground black pepper
  • 1/8 teaspoon pepperoncini peppers or 1/8 teaspoon cayenne pepper
  • For sandwiches
  • 1 lb cooked turkey breast , sliced (use your thanksgiving leftovers!)
  • 4 ciabatta rolls
  • 12 slices bacon
  • 1 avocado , halved, pitted, peeled, and thinly sliced
  • 1 Onion Relish:.
  • 2 In heavy medium pot, combine onions and enough water to cover and bring to boil, then strain.
  • 3 Return onions to pot and add sugar, red wine vinegar, and balsamic vinegar.
  • 4 Place over moderate heat and bring to simmer, reduce heat to low, and cook, uncovered, stirring occasionally, until onions are completely tender and have no bite left, about one and a half hours,
  • 5 (The liquid should be syrupy and coat the onions).
  • 6 Remove from heat and cool to room temperature.
  • 7 Aïoli:.
  • 8 In food processor or blender, purée yolk, garlic, mustard, and vinegar until smooth and creamy, 1 to 2 minutes.
  • 9 Combine oils, then, with motor running, slowly drizzle into processor until completely emulsified, about 2 minutes, (If aïoli gets too thick, add a small amount of warm water, 1 teaspoon at a time).
  • 10 Sprinkle in salt, pepper, and pepperoncini, cover with plastic wrap, and refrigerate until ready to use.
  • 11 Preheat oven to 350°F.
  • 12 Bacon:.
  • 13 In large, heavy skillet over moderate heat, cook 6 slices bacon, turning occasionally, until crisp, then transfer with tongs to paper towel–lined plate to drain.
  • 14 Repeat with remaining 6 slices.
  • 15 Set aside.
  • 16 Assemble Sandwiches:.
  • 17 Slice each ciabatta in half and place on large baking sheet.
  • 18 Place 4 ounces turkey on each of four ciabatta bottoms, then spread onion relish over meat.
  • 19 Lay 3 slices bacon on each of 4 ciabatta tops.
  • 20 Transfer baking sheet to oven and toast until bacon is crispy and edges of ciabatta turn light golden brown, about 5 minutes (the turkey does not have to get hot). Remove from oven and transfer bacon to other side of ciabatta, laying on top of onion relish.
  • 21 Divide avocado slices between sandwiches, placing on top of bacon.
  • 22 Spread aïoli evenly across each ciabatta top, close sandwiches, slice each in half, and serve.