Prepare a 12 cup muffin tin with liners.
Mix almond flour, oat flour, coconut sugar, baking powder, baking soda, and salt in a large bowl.
In separate bowl, whisk together eggs, maple syrup, milk, almond oil, vanilla.
Add wet ingredients to dry ingredients, and stir to combine - a few streaks of flour are okay. Then fold in rhubarb, which will also finish combining so no dry flour remains.
Preheat oven to 375 degrees F. Let batter sit while oven is preheating. This allows the flours to absorb the liquid ingredients. When oven has preheated, use a cookie scoop to add batter, almost near the top, of each liner. Top each muffin with three or four small pieces or rhubarb. Sprinkle with crushed almonds.
Put muffins in the oven and turn heat down to 350 degrees F. Bake for 22-23 minutes, until toothpick comes out clean. Let cool on a wire rack.