Spray a 9-inch square pan with cooking spray, and line the bottom with parchment paper.
In the mixing bowl of a stand mixer, mix the Butter, Sugar, and Vanilla until smooth.
Place the flour in a microwave-safe bowl, and microwave the Flour until it's hot, about 1 1/2 minutes, stopping, and stirring about halfway through heating.
Add the Flour and Salt to the mixing bowl and mix until smooth.
Melt the White Chocolate in the microwave at 10-second intervals, stirring between intervals, until melted.
Add the Eagle-brand milk to the melted White Chocolate, and stir until smooth.
Add the White Chocolate mixture to the mixing bowl, and mix on low until completely blended.
Add the Green Food Coloring Gel, a few drops at a time until you have a light green color.
Add half of the Lucky Charms (1 cup) to the Fudge
Pour the Fudge into the square pan, and press evenly into the pan with a spatula or the back of a large spoon.
Add the remaining Lucky Charms on top.
Refrigerate for at least 2 hours, or longer if needed, until the fudge is firm, and set.
Cut fudge into 1 to 2-inch squares, and place on a plate or platter to serve. Enjoy.