Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking dish by lining it with parchment paper.

In a mixing bowl, combine the ingredients for the crumble topping until they resemble wet sand, then set aside.

In a medium bowl, whisk together the dry ingredients: gluten-free flour, tigernut or almond flour, coconut sugar, cinnamon, baking powder, and baking soda.

In a large bowl, beat the wet ingredients: melted coconut oil, maple syrup, and any optional ingredients until smooth.

Gently fold the dry ingredients into the wet mixture until just combined, then add shredded carrots and optional add-ins.

Pour half of the batter into the lined baking dish, then layer it with cinnamon-sugar if desired, and add the remaining batter.

Crumble the reserved topping mixture evenly over the batter.

Bake for 40-45 minutes until golden brown and a toothpick comes out with a few moist crumbs.

Let the cake cool in the pan for 10-15 minutes, then transfer to a wire rack to cool completely.