Preheat oven to 425 degrees F.Line a baking sheet with parchment paper. Set aside.Cut the tomatoes into thick slices. Place all in a medium mixing bowl.In a small measuring cup, whisk together oil, Ranch mix and garlic. Pour over tomato slices and toss gently to coat.Layer tomato slices in one layer on the prepared sheet.Sprinkle Parmesan cheese on each slice.Roast for 15 minutes. If desired, broil for 2 minutes.Cool before serving.