Mix flour and baking powder together, then set aside.
In a medium saucepan over low heat, heat 2 cups of sugar, butter and white chocolate until melted. Keep a close eye on the mixture, as it can burn easily if you have it too hot. Remove from heat and let cool slightly. Add vanilla extract. Gradually add beaten eggs, whisking the mixture while adding. Add flour mixture and mix thoroughly.
Split cookie mixture into two bowls. Add red icing coloring to one bowl and green icing coloring to the other bowl. Add as much as you need to get the color you want. I probably used between ¼ to ½ teaspoon each.
Add half of the bag of M&M's to each bowl.
Chill cookie mixture for 1-2 hours.
When ready to bake, preheat oven to 350°F. Spray cookie sheet with cooking spray, or line with a silicone baking mat.
Scoop dough in tablespoons and roll into a ball. Roll dough balls into the remaining ½ cup sugar and place on cookie sheet 2 inches apart.
Bake for 10-12 minutes. Cool cookies on a wire rack.