Prep the Tomatoes
Core and slice tomatoes thinly.
Place in a colander, sprinkle with ½ teaspoon salt, and let drain at least 15 minutes.
Cook the Bacon
Fry bacon in a skillet over medium heat until crisp, about 10 minutes.
Drain on paper towels, saving drippings.
Toast the Bread
Leave 1 tbsp bacon drippings in skillet.
Toast bread slices on one side until golden.
Place toasted-side down on a baking sheet.
Mix the Cheese Topping
In a bowl, combine cheddar, mozzarella, mayonnaise, scallions, and parsley.
Mix until creamy.
Assemble the Toasts
Spread most of the cheese mixture over the untoasted side of each bread slice.
Crumble bacon evenly on top.
Add tomato slices and zucchini ribbons.
Dot with reserved cheese mixture and season with black pepper.
Bake
Preheat oven to 400°F (200°C).
Bake for 15–20 minutes, or until golden and bubbly.
Serve
Enjoy warm, straight from the oven.