Preheat oven to 350˚F. Lightly grease an 11x7" (27x20 cm) baking pan.
Make flax eggs by stirring together 2 tbsp ground flax meal and 5 tbsp water. Let sit for 15 minutes to thicken.
In a large mixing bowl, stir together oats, chopped nuts, coconut flakes, sugar, cinnamon, ginger, nutmeg, and salt.
In a separate bowl, mash the banana using a masher or the back of a fork. It should be pretty smooth – you don't want any large pieces. Add in milk, maple syrup, melted butter, flax eggs, and vanilla and whisk until smooth.
Add wet mixture to dry and stir well to combine. Fold in shredded carrots and golden raisins. Let the batter sit for 15 minutes, stirring every 5 minutes, then transfer to baking pan and bake for 25 minutes.
Meanwhile, to make the crumble topping, stir together the walnuts, golden raisins, coconut, melted butter and maple syrup until well coated.
After 25 minutes of baking, remove the oatmeal bake from the oven and top with the crumble topping in an even layer. Return to oven for 15 minutes, or until the top is light golden brown. Remove from oven and let cool.
Whisk together all ingredients for glaze. Wait until the baked oatmeal is cool, then drizzle the glaze over the top. Alternatively, you can slice and top each piece with glaze individually.
