Preheat oven to 450 degrees F. Scatter the onion, carrot and lemon pieces on a small baking sheet, set aside.
Drizzle the oil over the turkey breast and then season with salt, pepper, garlic, onion, paprika, dried thyme and chopped garlic, rubbing the spices to coat the breast evenly. Place on top of the vegetables on the baking sheet and then top with the fresh herbs. Place the pan in the oven and immediately lower the temperature to 350 degrees. Roast for 1 hour, cooking until the internal temperature reaches 165 degrees F. Start checking after 1 hour of roasting and continue checking every 10 to 15 minutes until the breast is cooked through.
Remove from the oven and let rest for about 15 to 20 minutes before slicing.
Place the bacon on a baking sheet, in a single layer. You might need two baking sheets to fit it all. Bake in a preheated 400 degree F oven until crispy, about 15 to 25 minutes, depending on how thick your bacon is. Transfer the bacon onto a plate lined with paper towels.
To assemble the sandwiches, spread mayo on one slice of toasted bread. Top with a piece of lettuce, a slice of ham, a few slices of carved roasted turkey and 3 half slices of bacon. Next, slather both sides of another piece of toasted bread and place on top of the bacon. Lay another slice of lettuce, 2 slices of tomato, more slices of turkey, another slice of ham and 3 more half slices of bacon. Spread another slice of toasted bread with mayo and then place on top. Cut into quarters and skewer each quarter with a long toothpick. Repeat three more times to make 4 large triple decker clubs. Serve right away. Enjoy!