Combine the gruyere and parmesan cheese in a small bowl. Set aside.
Place one sheet of puff pastry in the refrigerator. Gently unfold the second sheet on parchment paper or a lightly floured surface. Using a rolling pin, thin out the dough until it’s approximately 9 x 12 inches.
Sprinkle 1/2 the cheese mixture, 1/2 tablespoon sage, and 1 teaspoon Italian seasoning evenly over the puff pastry and gently press into the surface. Using a knife or bench scraper, lightly draw a line down the center of the dough lengthwise to use as a guide.
Starting on one side, roll the dough tightly toward the center, frequently pressing to prevent air holes. Repeat this step on the other side. Wrap the dough in plastic and then freeze or chill in the refrigerator until very cold, at least 20 minutes. Repeat with the remaining ingredients.
Preheat the oven to 425 degrees F, and line a large baking sheet with parchment paper.
Place one roll on the counter. Cut off a bit of each end, and then thinly slice the dough into 1/4 inch pieces, placing 1 inch apart on the baking sheet. (Note: If the dough begins to unroll while slicing, try cutting thicker palmiers and sliding each piece off the knife directly onto the baking sheet. They will come together while baking)
Brush each palmier lightly with olive oil, and sprinkle with a bit of salt and pepper.
Bake (in batches if necessary) for approximately 6 minutes, or until the side facing down is golden brown. Flip the palmiers and cook for an additional 3-5 minutes. Allow to cool before serving.