1. 1. Prepare the Mushroom and Spinach Filling: Heat the olive oil in a large skillet or Dutch oven over medium heat. Add the chopped yellow onion and cook until softened, about 3-4 minutes. Stir in the minced garlic and cook for another minute until fragrant. Add both the cremini and shiitake mushrooms to the skillet. Cook, stirring occasionally, until the mushrooms have released their liquid and are nicely browned, about 8-10 minutes. The mushrooms should look tender and slightly caramelized.

2. 2. Wilting the Spinach and Building Creaminess: Add the fresh spinach to the skillet with the mushrooms. Cook, stirring frequently, until the spinach has completely wilted, which usually takes about 2-3 minutes. Pour in the vegetable broth, scraping up any browned bits from the bottom of the pan. Reduce the heat to low. Stir in the softened cream cheese, sour cream, and 1/4 cup of grated Parmesan cheese until everything is well combined and the mixture is smooth and creamy. Season the filling with Italian seasoning, salt, and black pepper. Taste and adjust seasonings as needed. Remove the skillet from the heat.

3. 3. Assemble the First Layer: Preheat your oven to 375 F (190 C). Spread about 1/2 cup of the creamy spinach and mushroom filling evenly over the bottom of a 9×13-inch baking dish. This prevents the dumpling wrappers from sticking and creates a flavorful base. Arrange a single layer of dumpling wrappers over the filling, overlapping them slightly if necessary to cover the entire surface. Don’t worry if they don’t fit perfectly; slight gaps are fine.

4. 4. Layering the Lasagna: Spoon about one-third of the remaining spinach and mushroom filling over the dumpling wrappers, spreading it evenly. Sprinkle about one-third of the shredded mozzarella cheese over the filling. Repeat this layering process: add another layer of dumpling wrappers, followed by another third of the spinach and mushroom filling, and then another third of the mozzarella cheese.

5. 5. Final Layers and Baking: Place the last layer of dumpling wrappers on top. Spread the remaining spinach and mushroom filling over these wrappers, ensuring good coverage. Finish by sprinkling the remaining mozzarella cheese evenly over the top. You can also add a little extra grated Parmesan cheese at this stage for a richer crust.

6. 6. Bake Until Golden and Bubbly: Cover the baking dish loosely with aluminum foil. Bake for 15 minutes. After 15 minutes, remove the foil and continue baking for another 10-15 minutes, or until the cheese is melted, bubbly, and lightly golden brown. The edges of the dumpling wrappers should be tender. Let the lasagna rest for 5-10 minutes before slicing to allow it to set.

7. 7. Prepare Optional Tahini Dressing and Serve: While the lasagna rests, whisk together the tahini, lemon juice, water, and a pinch of salt in a small bowl until smooth and pourable. If it’s too thick, add a tiny bit more water, a teaspoon at a time, until it reaches your desired consistency. Garnish the finished lasagna with fresh chopped parsley and drizzle with the optional tahini dressing before serving.