• Preheat the oven to 180°C (350°F). Slightly oil an 8-inch x 8-inch baking dish or square tin. Set aside.
• In a large bowl, mix rolled oats, flour of choice, chopped walnuts, brown sugar, vanilla, and cinnamon.
• Add softened coconut oil and rub with your fingertips until it forms a breadcrumb-like texture.
• Set the bowl aside in the fridge while making the feijoa layer.
• Cut the ripe feijoa halfway, and use a teaspoon to scoop out the flesh. Use a knife to roughly chop in big chunks. Pack chunks in a measuring cup and repeat this step until you get 3 cups of feijoa.
• Place feijoa in another large mixing bowl with cornstarch, brown sugar, cinnamon, nutmeg or ginger, and lemon juice. Stir well.
• Spread the feijoa layer in an even layer onto the prepared dish.
• Sprinkle the crumble mixture all over the feijoa.
• Bake in the center rack of your oven for 25-30 minutes or until the fruits are cooked, bubbles form on the side of the pan, and the crumble topping is golden and crispy.
• Serve with a dollop of dairy-free vanilla ice cream or coconut yogurt.

Storage

• Store leftovers for up to 3 days in the fridge in an airtight container.