Preheat your oven to 350°F (175°C). Prepare two baking sheets by lining them with parchment paper to prevent sticking.
In a medium mixing bowl, whisk together the all-purpose flour, baking soda, and salt until well combined. Set this mixture aside for later use.
In a large mixing bowl, beat the softened butter, packed brown sugar, and granulated sugar using an electric mixer on medium speed until the mixture becomes light and fluffy, approximately 2 to 3 minutes.
Add the pure vanilla extract and the egg to the butter-sugar mixture, beating until fully incorporated and smooth.
Gradually incorporate the flour mixture into the wet ingredients, mixing just until the flour is fully absorbed. Do not overmix to keep the cookies tender.
Gently fold in the rolled oats, shredded coconut, semisweet chocolate chips, white chocolate chips, holiday-themed M&M's, chopped nuts, and dried cranberries or cherries. Ensure all ingredients are evenly distributed throughout the dough.
Using a cookie scoop or a regular tablespoon, drop rounded portions of dough onto the prepared baking sheets, leaving approximately 2 inches of space between each cookie to allow for spreading as they bake.
Place the baking sheets in the preheated oven and bake for 10-12 minutes, or until the edges of the cookies are golden brown, while the centers remain soft and slightly underbaked for a chewy texture.
After baking, remove the cookies from the oven and let them cool on the baking sheets for about 5 minutes. This will help them set before transferring them to wire racks to cool completely.
Notes
For a festive touch, arrange the cooled cookies on a decorative platter and dust with powdered sugar.