Step 1

Preheat the oven to 350 degrees F. Line a large baking sheet with parchment paper.

Step 2

Create the flax egg by combining ground flaxseed and water in a small bowl. Set aside for 5 minutes. It will thicken and gelatinize.

Step 3

Add the vegan butter, brown sugar, and sugar to a large bowl. Using a handheld electric mixer or a stand mixer, cream the butter and sugars together until light and fluffy (about 2-3 minutes). Add the flax egg, molasses, and vanilla extract. Cream together once more to combine.

Step 4

Add the quick oats, flour, baking soda, cinnamon, baking powder, nutmeg, and salt. Mix together until just combined.

Step 5

Scoop the oatmeal cookie dough into round balls and place on the baking sheet. Gently press the dough with your hands to flatten them a little. Bake for 13-15 minutes. Remove cookies from the oven while the center still appears slightly underbaked. They will continue cooking and firm up as they cool.

Step 6

While the oatmeal cookies cool, prepare the dairy-free vanilla buttercream frosting.

Step 7

Add the vegan butter, vanilla extract, and salt to a large bowl. Using a handheld electric mixer or a stand mixer, cream the butter until light and fluffy.

Step 8

Add sifted powdered sugar to the bowl. Cream together until the sugar is fully dissolved into the butter. Add 2-6 tbsp of non-dairy milk until it reaches your desired consistency.

Step 9

Transfer the vanilla buttercream frosting into a piping bag (or simply use a knife). Pipe (or spread) the frosting onto half of the oatmeal cookies. Cover with a second cookie to create cookie sandwiches. Enjoy!