• Cream together the sugar and butter, for about 2 minutes until light and totally mixed. 
• Add in the eggs, milk, and vanilla extract and stir in. 
• In a separate bowl combine the flour, baking powder and salt. 
• Slowly pour the dry ingredients into the wet ingredients while mixing. 
• With your hands, shape the dough into a ball. Cover the dough with plastic wrap or place in a ziplock bag. Place in the fridge for at least 2 hours, or overnight. 
• After the dough has been chilled, preheat the oven to 400 degrees. 
• Line a cookie sheet with parchment paper or a silicone liner. 
• Lightly flour your counter tops and roll out the dough. Roll the dough out to be about 3/8 to 1/2 inch thick. (Keep the extra dough in the fridge till needed)
• Cut your dough into Christmas tree shapes and place cookie dough about 1 inch apart on the cookie sheet. 
• Re roll the remaining dough and cut into trees.
• Place the cookie pan back in the fridge for about 5 to 10 minutes to chill again. 
• Bake cookies for 6 to 7 minutes, or just until the top is set. 
• Allow the cookies to cool for about 5 minutes on the pan, and then remove to a cooling rack to cool completely. 

For the Royal Icing:

• In a large bowl of a stand mixer, whisk together meringue powder and powdered sugar. 
• Slowly add in the water and vanilla while the mixer is running on medium speed. Continue beating the mixture until stiff peaks form, around 7 to 10 minutes (around 10-13 minutes if you're using a hand mixer)
• Whisk the food coloring into the icing.
• Add in 1/2 tsp of water at a time until you get the frosting into the texture of soft toothpaste. 
• Put about a third of the icing into a ziplock bag and snip the corner of the bag.
• Pipe the edges of the frosting onto the cooled cookies.
• Thin the remaining frosting another 1/2 tsp of water at a time until the icing is a honey like texture. 
• Spread the flood icing into the middle of the cookies, and allow it to settle some. Use a toothpick to fill in the gaps to spread the icing around to fill the whole cookie. 
• After icing all the cookies, go back to the first cookies and decorate. (Skip down to the decorating instructions).

For the Vanilla Frosting:

• Mix together the vanilla, butter, milk, and powdered sugar till frosting is smooth. 
• Fold in 4-5 drops of liquid green food coloring (or about 1/4 tsp of gel food coloring). Add more if needed for desired green color. 
• Scoop about 1/3 of the frosting into a ziplock bag. 
• Snip the corner of the ziplock bag, and carefully pipe an edge on the cooled cookies. 
• Fill in the middle of the cookie with frosting. 

For Decorating:

• Press a star shaped candy on to the top of the Christmas tree. 
• Pipe three small black lines onto each cookie to be the Christmas lights string. 
• Press mini m&ms side ways next to the lines for the Christmas lights.