In a large nonstick saute pan set over medium heat, cook the pancetta in batches until crispy, 3 to 4 minutes each side. Let drain on a paper towel and set aside.
For the aioli: In a food processor, add in the garlic and pulse. This not only breaks down the garlic, but it seasons the bowl. Then add in the lemon juice, mustard, sugar and egg yolks. Sprinkle with salt and pepper. Process until combined, about 10 seconds. Then slowly stream in the oil while the machine runs. Scrape down the sides of the bowl, add in the Romano cheese and process for 10 more seconds. Taste and adjust the seasoning with more lemon juice, salt and pepper if necessary.
For the sandwich build: Lightly toast the bread. Smear some aioli on each slice of bread. Top with 2 slices tomatoes, some avocado slices, 2 pieces of crisp romaine and 3 to 4 slices of crispy pancetta. Bite like a king.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.