Preheat oven to 350°
In a stand mixer with paddle attachment, cream butter and both sugars together on medium/high speed for 3-4 minutes until lighter in color and fluffy. This step is important to getting the right texture for the cookies.
Add in vanilla extract along with both eggs, one at a time and mix until combined.
In a medium separate bowl, whisk together flour, baking powder and salt.
Add dry into the wet ingredients and mix until it becomes dough, then stop mixing.
Split dough into three bowls evenly. In one bowl, add red food coloring, blue in the next and if you have white food coloring, add it into the third bowl or leave plain. Mix colors into dough.
Add in M&Ms evenly to the three bowls. Add the white chocolate chips to the blue bowl and split the semi-sweet chips between the red and white (or plain dough)
Using a small cookie scoop. scoop out one scoop of red, one scoop of white and one scoop of blue and gently press inward. See photo below.
Don't make them round in the palms of you hands. Just plop them down on a parchment lined baking sheet (aluminum restaurant grade baking sheet if you have one). Place them two inches apart, 6 to 8 per tray. Add extra M&Ms to top and sprinkle with flake sea salt. The darker the baking sheet, the quicker the bottoms will brown
Bake on the middle rack for 10-11 minutes.
As soon as you pull them out of oven, take a large round cookie cutter or a glass bowl larger than the cookie and gently swirl around the cookie to make it tight and round. After a minute, gently remove from cookie sheet and transfer to a wire rack. Do NOT over-bake. They should be soft cookies.