Preheat your oven to 375°F (190°C).
This will set a good baking temperature for your dip.
In a medium bowl, combine mayonnaise, sour cream, and water.
Whisk until these components are well blended.
Add minced garlic, ranch dressing mix, and Italian cheese blend into the mixture.
Stir thoroughly to integrate the flavors together.
Incorporate the thawed and well-drained spinach along with the Parmesan cheese.
Fold these gently to avoid breaking the spinach leaves.
Transfer the mixture to a baking dish and spread evenly.
Bake for about 20 minutes or until the top is golden and bubbly.