For the Burgers:

1. Preheat the oven to 400°F. Place the halved head of garlic on a sheet of tin foil. Drizzle the exposed cloves with olive oil and sprinkle with salt.
2. Wrap the foil around the garlic to form a package. Place in the oven, directly on an oven rack, for 40-45 minutes, or until the cloves are golden and caramelized (HINT: this is a great time to make your aioli and prep your burger toppings).
3. Remove the garlic from the oven and allow it to cool slightly before handling. Once cool enough, squeeze out the roasted cloves into a large bowl.
4. Mash the cloves with a fork until a paste forms. Mix in the mustard, Worcestershire sauce, onion powder, salt, and a generous amount of black pepper. Stir well to combine these ingredients.
5. Fold in the ground beef last, using your hands to mix the flavorings into the meat. Form the mixture into 4 or 6 patties, depending on the size you want.
6. Heat a large cast-iron skillet over medium heat and add a couple teaspoons of olive oil. Add the salami slices, in batches, in an even layer. Cook until crispy, about 1 minute per side. Remove and drain on a plate lined with paper towels. As they cool, they will get even crispier.
7. Once all the salami is crisped, add the burger patties to the drippings in the same pan. Cook for 4-5 minutes per side, adding the sliced cheese during the last minute of cooking time. Allow the cheese to melt and then remove the pan from the heat.
8. Top the burgers with the crispy salami and then transfer them to the burger buns. Top with the aioli and desired garnishes and serve.

For the Aioli:

1. Combine everything in a food processor and pulse until very well combined and mostly smooth. Season, to taste, with salt and pepper. Keep in an airtight container in the fridge for up to two weeks.