Preheat the oven to 350°F. Line standard 12-muffin pan(s) with parchment liners.
Measure the cassava flour by scooping it directly out of the bag using a dry measuring cup, then use the back of a straight knife to evenly scrape the excess flour from the cup. Cassava flour tends to go airborne easier than other flours. Be careful not to breath it in while scooping or stirring.Gently add the rest of the dry ingredients to the bowl and stir until combined.
Put the first four wet ingredients (oil, coconut milk, sugar, vanilla) into another large bowl and stir or whisk well. Fold in the raisins, walnuts, and zucchini.
Add about 1/3 of the dry ingredients to the bowl with the wet ingredients and fold. Repeat until all of the dry and wet ingredients are folded together.
Beat the aquafaba in a medium-sized bowl using a hand mixer or immersion blender until it turns into a stiff meringue. You'll know it's ready when you can turn the bowl upside down without the meringue sliding out of the bowl.
Gently fold the meringue into the muffin batter (see notes below).
Fill the muffin liners 3/4 of the way. Bake until a cake tester or toothpick comes out clean; this will take about 20 minutes.