Preheat the oven to 350°F and line baking sheet with parchment paper. Set aside.
Whisk together the flour, granulated sugar, baking powder, and salt until well combined. Set aside.
In a large bowl, using a hand mixer or stand mixer fitted with a paddle attachment, beat the eggs; then, add in the melted butter, vegetable oil, milk and vanilla extract, and continue to mix until completely smooth and creamy, about 3 minutes.
Pour the wet ingredients into the bowl with dry ingredients and mix together with a large spoon or rubber spatula.
Divide the mixture into two equal parts and add cocoa powder to one part of the dough, and mix until combined.
Roll the dough into small balls, using about 1 tablespoon of dough for each ball, and arrange the dough balls on the prepared baking sheet, 2-inches apart. You will need to work in batches, or use more than one baking sheet. Flatten the dough balls just slightly and decorate with red and green M&Ms, white chocolate chips, sprinkles, and any other sweet decorations that you like, or have on hand.
Bake cookies for 9 minutes, or until tops begin to crack and edges feel just set. Do not over bake or the cookies will be crunchy instead of soft.
Remove cookies from the oven and allow them to cool on the baking sheet for 2 to 3 minutes before transferring to a wire rack to cool completely.
Repeat the baking process with the remaining dough.
Store the cooled cookies in an airtight container with a layer of wax paper or parchment between each layer of cookies so they don’t stick to each other. Cookies will keep for several days at room temperature.