Preheat oven to 400°F (200°C).
Wash and chop spinach, then cook in a skillet over medium heat until wilted (3–5 minutes).
Let spinach cool, then squeeze out excess water.
Slice zucchinis lengthwise and trim ends so slices lay flat.
Arrange zucchini slices on a baking sheet, drizzle with olive oil, and lightly salt.
Bake for 15–20 minutes until softened. Let cool slightly on paper towels.
In a bowl, mix vegan ricotta, cooked spinach, basil, Italian seasoning, and salt.
Spread marinara sauce on the bottom of an 8×8 baking dish.
Spread filling over each zucchini slice and roll them up tightly.
Place rolls seam-side down in the baking dish.
Top with extra marinara sauce and sprinkle vegan mozzarella on top.
Bake for 20 minutes, until hot and cheese is melted.
Let cool a few minutes before serving.