Preheat your oven to 350°F (175°C). Grease and flour your cake pan.
In a mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Add the almond milk, vegetable oil, and vanilla extract. Mix until smooth.
Pour the batter into the prepared cake pan. Bake for 30 minutes or until a toothpick inserted into the center comes out clean.
Let the cake cool completely before frosting.
For the frosting, beat the vegan butter until creamy. Gradually add the powdered sugar, almond milk, and vanilla extract. Mix until smooth and fluffy.
Fold in the crushed vegan chocolate sandwich cookies.
Spread the frosting over the cooled cake. Serve and enjoy!