Preheat the oven to 350°F. Line two baking trays with parchment paper. In a small bowl, make flax “eggs” by whisking together the ground flaxseed with 6 tablespoons warm water and allow to sit for 10 minutes.
In a large bowl, whisk together the coconut oil and sugar until smooth. Add the flax “egg” mixture and whisk until the mixture is smooth and thickened. Mix in the almond butter, maple syrup, and vanilla.
In a medium bowl, stir together the oat flour, ground almonds, baking soda, and salt, then stir into the wet ingredients. Add the oats, walnuts, and cranberries, and mix until well-incorporated.
Scoop cookie batter by heaping tablespoons, placed 2 inches apart onto prepared baking trays. Flatten slightly with a spatula or your fingertips. Bake for 10 to 12 minutes, rotating trays midway through baking to ensure even cooking. Let cool on the baking tray for about 5 minutes, then transfer to a wire cooling rack to cool completely before serving.