From the Recipe Shoebox.
2 cups semisweet chocolate chips, divided
1 can (14-ounces) sweetened condensed milk, divided
8 oz. white baking chocolate (or 1-1/2 cups white chocolate chips)
1-1/2 tsp. peppermint extract (we like the Watkins peppermint extract from Walmart--it's cheaper and has a better flavor)
2 drops green food coloring
1 tsp. shortening (like Crisco)
1/2 cup Andes mint chips (or regular Andes mints chopped up)
Line a square 8x8 or 9x9-inch baking pan with tinfoil or parchment paper and lightly spray with nonstick spray.
In a small saucepan, combine 3/4 cup sweetened condensed milk with 1 cup chocolate chips. Heat over medium-low heat. Stirring frequently, heat until chocolate is melted and mixture is smooth.
Spread the chocolate mixture evenly in the bottom of the prepared pan. Place the pan in the refrigerator for 5-10 minutes while you prepare the next layer.
Grab a second small saucepan and combine 8 oz. white chocolate (either white baking chocolate or 1-1/2 cups white chocolate chips) along with the rest of the sweetened condensed milk.
As with the first layer, heat over medium-low heat, stirring frequently, until the mixture is melted and smooth. Then add 1-1/2 tsp. peppermint extract and 2 drops of green food coloring.
Add additional food coloring drop-by-drop until the desired color has been reached, then gently pour the green/minty layer over the set chocolate layer, taking care to keep the layers separate.