Preheat oven to broil / grill settings on high heat. Arrange oven shelf to the middle of your oven.
Combine the oil, garlic and 4 teaspoons of the seasoning together in a small bowl. Brush the bottoms of each mushroom with the garlic oil mixture and place each mushroom, oil side down, on a lightly greased baking sheet / tray.
Fill each mushroom with 2 tablespoons of the pizza sauce per cap, 1/4 cup of mozzarella cheese, 6 pepperoni miniatures and tomato slices. Broil / grill until cheese has melted and is golden in colour (about 8 minutes).
To serve, sprinkle with the remaining Italian seasoning (or mixed herbs), and season with salt and pepper to taste.
Notes
*I find using dry cheese such as shredded mozzarella gives the best results. Using fresh mozzarella may cause the mushrooms to release some liquid during the broiling / grilling process. *For the miniature pepperonis, I bought normal-sized pepperonis and cut them with an apple corer like this one to get miniature sized ones. (I used 8 slices.) However, you can use whatever you can find! TIP: Do NOT over bake them! They WILL release a lot of liquid if left in the oven for too long! Make sure your oven is preheated well and HOT when putting them in.