For the maple-brown sugar pancetta
To assemble and serve
Preheat oven to 375°F.
Line a baking sheet with foil and arrange pancetta slices in a single layer on top. Bake for 18 to 20 minutes or until almost crispy.
Meanwhile, combine brown sugar and maple syrup in medium mixing bowl and whisk thoroughly. Set bowl on top of oven while pancetta is baking to keep warm until ready to use.
In the bowl of a food processor or by hand combine the garlic, salt, and lemon juice and let sit for 5 to 10 minutes. Add the basil and mayonnaise and pulse or stir to combine. Adjust seasoning as needed.
When pancetta is ready, brush each slice with a generous amount of maple-brown sugar glaze, and bake for an additional 5 to 8 minutes, being careful not to burn. Remove from oven and let cool for at least 10 minutes before serving.
To build sandwiches begin by spreading 1 to 2 tablespoons of basil aioli on both sides of toasted sourdough. Top bottom slice with 1/4th of sliced avocado, some butter leaf lettuce, 2 thick slices of beefsteak tomato (seasoned to taste with salt and pepper), 1/4th of the glazed pancetta, and top slice of toasted sourdough. Serve immediately. Any additional aioli can be stored covered in the refrigerator for up to 3 days.