Prepare the zucchini: Cut the zucchini into thick, even rounds and pat them dry with paper towels. Lightly coat each slice with flour on both sides, then shake off the excess so only a thin layer remains.
Brown the zucchini: Heat the olive oil in a large skillet over medium-high heat. Arrange the zucchini in a single layer and lightly sprinkle with salt and black pepper. Cook until golden on the bottom, about 3 to 4 minutes, then flip and brown the second side. Work in batches if needed, adding a little more oil between batches. Transfer the browned zucchini to a plate.
Start the sauce: Reduce the heat to medium. Add the garlic and Italian seasoning to the same skillet and cook for about 30 seconds, just until fragrant.
Make the cream sauce: Pour in the heavy cream, add 1/3 teaspoon each of salt and black pepper, and give everything a good stir. Let the sauce come to a gentle simmer, then add the Parmesan and stir until it melts into the cream and the sauce begins to thicken.
Finish the dish: Return the browned zucchini to the skillet and gently stir until the slices are coated in the creamy sauce. Let everything simmer together for 3 to 5 minutes, until the zucchini is tender and the sauce has thickened slightly. If the sauce becomes too thick, stir in a small splash of water until it reaches the consistency you like.