Preheat the oven to 375 degrees. While the oven is preheating, add 1 tablespoon of unsalted butter to a small skillet and bring to medium heat. Once warm add the sliced shiitake mushrooms to the skillet and stir to coat with butter. Cook on low heat for about 10 minutes, stirring occasionally, until mushrooms begin to shrink and brown in color.
While the mushrooms are browning prepare the olive oil sauce. Combine remaining olive oil, grated Parmesan cheese, minced garlic, red pepper flakes, ground black pepper and oregano into a small bowl. Stir until well combined. Brush olive oil mixture evenly onto prepackaged naan bread slices until none remains.
Grate the white cheddar and Edam cheeses into small pieces. Add equal parts to each naan bread slice over the olive oil mixture. You can add more or less depending on your preference. Sprinkle shredded or fresh mozzarella cheese over top getting a nice combination all over each flatbread.
By now the mushrooms should be nearing completion. Add an even amount to each flatbread. Add chopped sun-dried tomatoes* throughout each flatbread into any gaps of toppings. Finally sprinkle chopped fresh rosemary all over each flatbread pizza.
Place flatbreads on a pizza stone or parchment paper lined cookie sheet and place in the oven for about 10 minutes or until cheese is melted. Serve warm and top with additional rosemary, red pepper flakes or Parmesan cheese. Enjoy!