Portobello Mushroom Burger with Avocado Chimichurri

Ingredients (17)

• 2 large portobello mushrooms
• 1 red bell pepper
• 1/2 red onion
• large handful of fresh spinach
• Extra virgin olive oil
• 1 teaspoon dried oregano
• kosher salt and freshly ground black pepper
• 1 avocado
• 3 cloves garlic
• 1/4 cup olive oil
• 1/4 cup flat leaf parsley leaves
• 1/4 cup cilantro leaves
• juice of 1 lemon
• 1 teaspoon red wine vinegar
• pinch of red chili flakes
• 2 pieces flatbread pitas or 2 soft burger buns
• Smoked mozzarella cheese