Add the butter, eggs, sugar, and cocoa powder to one bowl and mix well.

To the egg mixture add the flour, vanilla, and salt. Stir to combine.

Add the butter, eggs, and sugar to another bowl and mix well.

To the egg mixture add the flour, mint extract, green food coloring, and salt. Stir to combine.

Into a 9x13 inch pan drop the brownie into the pan in scoops. Leave room between them.

Add the blonde mint batter between the chocolate brownie batter. In a checkerboard pattern.

Using a spatula, blend the two batter together to get a swirl pattern. I made three passes lengthwise through the batter and another three passes crosswise.

Bake at 350 degrees for 25 minutes or until cooked through.

Let cool, cut into squares and enjoy the minty, fudge taste.