Preheat oven to 350 degrees.
Line cookie sheet with parchment paper
Separate green, orange, brown and purple M&M's into a small bowl
Using a medium bowl combine the flour, baking soda, salt, and cocoa powder together.
Mix well to blend all ingredients. Set aside.
With the electric mixer cream the butter and sugars (bottogether.
Add in the eggs and vanilla. Beat to mix well into the butter and sugar mixture.
Slowly begin to add small amounts of the dry ingredients into the butter, sugar, egg and vanilla mixture until all of the dry ingredients are combined.
With your hands begin making small dough balls. (about the size of a small ice cream scoop or 2 inches)
Again using your hands press the different colored M&M's into each round cookie dough ball.
Bake at 350 degrees for 9-11 minutes. Remove out of the oven and allow to cool slightly on the cookie sheet. Then transfer the cookies to a wire rack to cool completely.
Scoop the frosting into a microwave safe bowl and heat for 15 second to soften it
Mix in the drops of neon green gel food coloring
Using the flavor injector, place the needle into the bowl and pull the knob up on the injector to pull up some frosting
Poke the side of the cookie and inject frosting into the cookie until the top cracks
Repeat step on all cookies