Line a square baking dish (9x9inches, or 8x8 inches)
Separate your sweetened condensed milk evenly into two medium sized microwave safe bowls. 14 oz sweetened condensed milk
Add the white chocolate chips to one of the bowls. 1 1/2 cups white baking chips
Microwave the white chocolate mixture for 30 seconds, then stir as much as you can for about 30 seconds. Microwave for another 30 seconds and stir till fudge is totally smooth. (Microwave for another 15 seconds as needed)
Add the peppermint extract and green food coloring to the mixture, and stir it in until mixed smooth. Set aside until needed. 1 tsp peppermint extract, 5 drops green food coloring
Add the semi sweet chocolate chips to the other bowl of sweetened condensed milk. 1 1/2 cups semi sweet chocolate chips
Microwave the chocolate mixture for 30 seconds, then stir as much as you can for about 30 seconds. Microwave for another 30 seconds and stir till fudge is totally smooth. (Microwave for another 15 seconds as needed)
Add spoon-fuls of both the green white chocolate mixture, and the chocolate mixture, alternating between the two into the prepared pan.
Pat the pan against the counter to remove some of the air bubbles.
Use a butter knife to swirl the fudges together to make a marble texture.
Allow the fudge to set for several hours at room temperature till hard, or put the fudge in the fridge for about 2 hours for a quicker set.
Lift the fudge out of the pan and slice the edges off the remove the rough pieces.
Slice the fudge into pieces, and enjoy, or store in an airtight container until needed.