Prepare the Pie Crust: Preheat the oven to 375°F (190°C). Fit the pie crust into a 9-inch pie plate. Prick the bottom with a fork, line with parchment paper, and fill with pie weights or dried beans. Bake for 12 minutes, remove the weights, then bake for another 5 minutes until lightly set but not browned. Allow the crust to cool slightly.

Drain the Tomatoes: Arrange the tomato slices on paper towels. Sprinkle with ½ teaspoon salt and let them stand for 20 minutes. Pat both sides dry thoroughly with additional paper towels. This step removes excess moisture and helps prevent a soggy pie.

Prepare the Cheese Mixture: In a bowl, combine the shredded cheddar, mozzarella, chopped basil, green onions, remaining ½ teaspoon salt, and black pepper. Toss until evenly mixed.

Make the Creamy Topping: In another bowl, stir together the mayonnaise, cheddar cheese, Parmesan, garlic powder, and oregano until smooth.

Assemble the Pie: Spread one-third of the cheese mixture over the cooled crust. Arrange half of the tomato slices on top. Repeat with another layer of cheese and the remaining tomatoes. Finish with the remaining cheese mixture. Spread the mayonnaise topping evenly over the entire pie, covering the tomatoes.

Bake: Bake for 30–35 minutes, or until the topping is golden brown and bubbling around the edges. If the crust begins browning too quickly, loosely cover the edges with aluminum foil.

Cool: Allow the pie to cool for 15–20 minutes before slicing. This resting time helps the filling set and makes cleaner slices.

Serve: Garnish with fresh basil and cracked black pepper if desired. Serve warm or at room temperature.