Step 1

Prepare an 8-inch cake pan (see Notes) by lining with parchment or foil, or directly greasing the pan with a splash of oil.

Step 2

Add nut butter, oil, and syrup to a microwave-safe mixing bowl. Melt in the microwave for about 15 seconds.

Step 3

Combine the dry ingredients (oats, baking soda, flax, espresso powder, cocoa powder) together in a blender jar. Blend on high speed for a minute or until the oats and flax have been ground into a fine flour. (Skip this step if you're already using oat flour and ground flaxseed.)

Step 4

Add the dry ingredients to the microwaved mixing bowl along with vanilla extract and plant milk. Mix thoroughly to combine.

Step 5

Press evenly into the bottom of the prepared cake pan and slightly up the sides as well.

Step 6

Add nut butter, oil, and syrup to a microwave-safe mixing bowl. Melt in the microwave for about 15 seconds.

Step 7

Combine the dry ingredients (oats, baking soda, flax) together in a blender jar. Blend on high speed for a minute or until the oats and flax have been ground into a fine flour. (Skip this step if you're already using oat flour and ground flaxseed.)

Step 8

Add the dry ingredients to the microwaved mixing bowl along with vanilla extract and plant milk. Mix thoroughly to combine.

Step 9

Press evenly into the prepared cake pan.

Step 10

Optional: press chocolate chips or chopped nuts into the top of the cookie layer.

Step 11

Bake at 350 °F (175 °C) for 24 to 25 minutes.

Step 12

Let cool to room temperature before slicing.