In a large bowl, combine flour and salt. Add the cold cubed butter and use a pastry cutter or your fingers to blend until the mixture resembles coarse crumbs.
Gradually add ice water, one tablespoon at a time, until the dough comes together. Shape into a disc, wrap in plastic wrap, and refrigerate for 30 minutes.
Prepare the Filling:
Heat olive oil in a skillet over medium heat. Add garlic and sauté for 30 seconds.
Add zucchini and spinach, cooking until just wilted, about 3–4 minutes. Season with salt, pepper, and herbs if using. Remove from heat and let cool slightly.
In a bowl, mix the sautéed vegetables with ricotta and Parmesan cheese.
Assemble the Galette:
