For the beef: Combine the chuck, bell peppers, onions, garlic, tomatoes, Italian seasoning, fennel seeds, 2 1/2 teaspoons salt, and some pepper in a slow cooker. Cook on the low setting for 8 hours. Use a ladle to remove some of the excess fat from the surface, then coarsely shred the beef with two forks. Season with salt and pepper.
For the aioli: Place the egg, garlic and Dijon in a food processor and pulse to combine. With the motor running, add the olive oil and vegetable oil in a very slow steady stream until it is all incorporated. Add the in the giardiniera to the food processor and pulse until chopped. Season with salt and pepper.
Spread about 2 tablespoons of the aioli on both sides of the bread and then make sandwiches with the shredded beef. Serve immediately.
In a small bowl, mix together the basil, marjoram, oregano, parsley, granulated garlic, rosemary, thyme and red pepper flakes. Store in a jar with a tight-fitting lid.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.
This recipe has been updated and may differ from what was originally published or broadcast.