Portobello mushroom boats with cauliflower puree

Ingredients

• 6-8 large Portobello mushrooms
• 1 tsp dried oregano
• 600 g cauliflower, cut into florets
• 1 clove of garlic, finely chopped
• 1/4 tsp chives, finely chopped + more for garnish
• 3-4 tablespoons unsweetened almond milk
• Sea salt and black pepper to taste