Preheat the Oven: Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with cooking spray or a little olive oil.

Prepare the Vegetables: Wash and thinly slice the zucchinis and potatoes into even rounds, about ⅛ inch thick, for uniform cooking. Use a mandoline slicer if available for precise, even slices.

Make the Cream Sauce: In a medium bowl, combine the heavy cream, salt, pepper, herbes de Provence, garlic powder, and onion powder. Whisk together until well mixed.

Layer the Vegetables: Begin layering the potatoes in the prepared baking dish, slightly overlapping them. Add a layer of zucchini slices over the potatoes, slightly overlapping as well. Repeat the process, alternating between the potato and zucchini layers until all the slices are used, ending with a layer of potatoes on top.

Add the Cream Mixture: Pour the cream mixture evenly over the layered vegetables, ensuring that all the layers are well-coated.

Cheese Layer: Sprinkle 1⅓ cups of the grated parmesan cheese evenly over the top of the vegetables, reserving the remaining ⅓ cup for later.

Bake: Cover the baking dish with aluminum foil and bake in the preheated oven for 45 minutes. After 45 minutes, remove the foil, sprinkle the remaining parmesan cheese on top, and bake for an additional 15-20 minutes, or until the top is golden brown and the potatoes are tender when pierced with a fork.

Garnish and Serve: Remove the zucchini and potato bake from the oven and let it rest for a few minutes. Sprinkle chopped chives over the top for a fresh pop of color and flavor before serving.