Prepare and 8x8 baking pan by lining with parchment paper. Place the pan in the freezer.
In a small saucepan melt white chocolate squares with 1/2 the container of vanilla frosting. Add the food coloring and mint extract and mix well. Once melted and a smooth consistency, remove pan from freezer and evenly spread chocolate mixture in the pan. Return the pan to the freezer.
In the same saucepan, melt 6 ounces semi-sweet chocolate with the remaining half of the vanilla frosting. Once melted and a smooth consitency, remove pan from the freezer and evenly spread chocolate on top. Return the pan the the freezer.
In same saucepan, melt the remaining 2 ounces of semi-sweet chocolate with the oil until a smooth consistency. Allow to cool slightly before placing in a small sandwich baggie.
While chocolate sauce is cooling in the baggie, remove the pan from the freezer. If the mixture is still warm, allow to remain in the freezer until completely cooled. Remove the parchment paper from the pan when completely cooled. Invert the fudge so that the parchment paper can be peeled away.
Cut a small tip from the corner of the sandwich baggie and drizzle the chocolate sauce over the fudge as a garnish. Allow to sit a few minutes while sauce sets up, then cut into small squares. Arrange on a platter and serve. Leftovers may be stored in an air-tight container.