Step 1: Preheat Your Oven
Preheat your oven to 250°F (120°C).
This low temperature allows the zucchini slices to dry out slowly and become perfectly crispy.
Proper preheating sets the stage for even baking.

Step 2: Prepare the Zucchini
Wash and thoroughly dry the zucchinis.
Slice them into thin rounds, about 1/8-inch thick, using a mandolin or sharp knife.
Consistent slices are key to even baking and crispiness.

Step 3: Remove Excess Moisture
Lay the zucchini slices on a paper towel and sprinkle lightly with salt.
Let them sit for about 10 minutes to draw out excess water.
Pat them dry gently with another paper towel to remove surface moisture.

Step 4: Season the Zucchini Slices
In a large bowl, toss the zucchini slices with olive oil until evenly coated.
Add the sea salt, garlic powder, smoked paprika, and black pepper.
If using Parmesan, sprinkle it in and toss gently to coat the slices.

Step 5: Arrange and Bake
Line a baking sheet with parchment paper.
Place the zucchini slices in a single layer without overlapping.
Bake for 1.5 to 2 hours, flipping halfway through, until crispy and golden.

Step 6: Check for Crispiness
At the 90-minute mark, start checking your chips.
They should be golden brown and crisp to the touch.
Allow them to cool for 5 minutes after baking to firm up even more.