If you are preparing your own mayo base, whisk up the egg yolk with Dijon and lemon juice then slowly stream in oil, letting it lightly pour down the sides of the bowl while you whisk. Stream in oil until aioli forms and season with sea salt to taste.
Combine homemade aioli or store-bought mayo with ketchup, relish, garlic, salt, pepper and herbs.
Heat oven to 375F. Preheat a flat griddle or cast-iron skillet over medium-high heat.
Arrange bacon on slotted pan and bake until crisp, 15-18 minutes.
Combine beef with Worcestershire and season with kosher salt and pepper. Form 6 patties thinner at the center for even cooking and drizzle them with oil. Cook patties 8 minutes, turning occasionally. Melt folded Swiss cheese over each burger during the last minute or 2 of cook time.
Place cheeseburgers on toasted roll bottoms and top with bacon, lettuce, tomato and onion. Slather tops with dressing and set in place.