Vegan Portobello, spinach, red onion, zucchini, and vegan cheese salad

Ingredients:
4 large portobello mushrooms, stems removed
2 tablespoons olive oil
Salt and pepper
1 large red onion, sliced
2 medium zucchini, sliced
2 cups fresh spinach leaves
1 cup vegan cheese, shredded
Caesar dressing (see recipe below)
Directions:
Preheat the oven to 400°F (200°C).
Brush the portobello mushrooms with olive oil and season with salt and pepper. Place them on a baking sheet and roast in the oven for 15-20 minutes, until tender.
While the mushrooms are cooking, heat a tablespoon of olive oil in a large skillet over medium heat. Add the sliced red onion and zucchini and cook for 5-7 minutes, until the vegetables are softened and lightly browned.
Arrange the spinach leaves on a large platter or individual plates. Top with the roasted portobello mushrooms and the sautéed red onion and zucchini.
Sprinkle the shredded vegan cheese on top of the vegetables.
Drizzle the Caesar dressing over the salad.
Serve immediately.
For the Caesar dressing:
Ingredients:
1/2 cup vegan mayonnaise
2 cloves garlic, minced
1 tablespoon Dijon mustard
2 tablespoons capers, drained and chopped
1 tablespoon lemon juice
2 tablespoons nutritional yeast
Salt and pepper to taste
2-3 tablespoons water, to thin the dressing as needed
Directions:
In a small bowl, whisk together the vegan mayonnaise, minced garlic, Dijon mustard, capers, lemon juice, nutritional yeast, salt, and pepper.
Gradually whisk in water until the dressing reaches your desired consistency.
Taste and adjust the seasoning as needed.
Use immediately, or store in an airtight container in the refrigerator for up to one week.