1. Use a microplane to grate the fresh garlic and lemon zest into a mixing bowl, add the lemon juice, mayonnaise, salt and pepper. Stir to combine, then set aside.
For the Crostini
1. Preheat the oven to 350 degrees F.
2. Place the bacon slices on a baking sheet, sprinkle freshly ground pepper all over the bacon and place into the oven for 15-20 minutes, or until cooked and crispy. Once done, remove from the oven and cut each slice into thirds, set aside.
3. Place the bread slices onto a baking sheet, drizzle with a little olive oil and bake in the oven until slightly golden, about 12 minutes. Once done, remove fromt the oven and set aside.
4. Peel and remove pit from the avocado then thinly slice, squeeze a bit of lemon juice over the avocado slices to prevent browning.
5. To assemble the crostini, smear some mayonnaise add 2-3 thin slices of avocado, 3-4 thin tomato slices, bacon and a parmesan shaving.