Two Cheese Scalloped Potato Stacks



1 ½ lbs. potatoes/sweet potatoes (or combo- like I used. =approx. 1 med to large sweet potato + 1 med to large russet potato)
1 tsp chopped fresh rosemary divided
¼ cup grated mozzarella cheese
¼ cup grated Gruyere cheese
1 Tbsp butter
⅓ cup heavy cream
¼ tsp salt
1 clove garlic, pressed
Pepper, to taste
Fresh rosemary or thyme, for garnish