Prepare an 8×8 inch baking pan with non-stick baking spray and parchment paper.

In a large mixing bowl combine all of the base ingredients and mix until a coarse sand-like texture is achieved.

Place the base mixture into the prepared baking pan and very firmly and evenly press down. Set aside.

In the bowl of a stand mixer cream the butter on high until light and fluffy. This should take approximately 5 minutes.

Add in the icing sugar, milk, mint extract, and salt and mix on low until combined.

Add in 2 drops of green food coloring if desired.

Turn the mixer up to high and allow the frosting the whip for 5 minutes.

Spread the mint frosting evenly over the base layer and set aside.

Combine the chocolate and butter in a microwave-safe bowl and heat in 30-second intervals until fully melted and smooth. Make sure to stir gently after each interval.

Spread the chocolate evenly on the mint buttercream layer and add sprinkles/toppings if desired.

Allow to fully cool and set for at least 1 hour in the refrigerator before slicing. See slicing tips in post.

Cut into 16 squares and enjoy! Store the leftovers in an airtight container in the fridge for up to 7 days.