For the Focaccia BLT:

1. Start by roasting the garlic for the basil aioli. Preheat the oven to 400°F. Slice the top ¼ inch off the garlic bulb to expose the cloves. Drizzle with 1 tbsp olive oil, season with salt, and wrap tightly in foil. Roast for 40–45 minutes (or air fry at 380°F for 18–25 minutes), until the cloves are golden, soft, and jammy. Set aside to cool slightly.
2. Cook the bacon. While the garlic roasts, line a baking sheet with parchment paper and arrange the bacon in a single layer. Bake at 400°F for 16–18 minutes, or until crisp. Start checking around 14 minutes, as cooking time will vary depending on the thickness of your bacon. Transfer to a paper towel-lined plate to drain.
3. Make the basil aioli. Once the garlic is cool enough to handle, squeeze the roasted cloves from their skins into a blender or container for an immersion blender. Add the mayonnaise, basil, lemon zest, lemon juice, salt, and pepper. Blend until smooth. Stir in the parmesan cheese, and taste to adjust the seasoning as needed.
4. Prep the tomatoes. Arrange the tomato slices on a plate and drizzle with olive oil. Season generously with flaky sea salt.
5. If desired, lightly toast the focaccia until warm and crisp around the edges.
6. Assemble the sandwich. Spread a generous layer of roasted garlic basil aioli on both cut sides of the focaccia. Layer with the lettuce, followed by 1–2 slices of tomato and 4–5 slices of bacon. Top with the remaining focaccia and serve immediately.