In a medium mixing bowl, combine the flour, baking soda, and salt. Set aside.
In another medium mixing bowl, cream the butter, oil, sugar, and powdered sugar together until fluffy.
Then, add the egg and vanilla, beating just until combined.
Gradually stir in the dry ingredients and continue to mix just until a dough forms. The dough will be soft and slightly sticky.
Wrap the dough in plastic wrap and refrigerate for one hour.
Preheat the oven to 350 degrees and prepare 2 baking sheets with parchment paper.
Fill a small bowl with Christmas sprinkles. Scoop the dough with an ice cream scoop or spoon, or cut the dough into even pieces, and roll into balls. Then, roll the dough balls in the sprinkles.
Place the cookie dough balls on baking sheets, spacing about 2 inches apart.
Bake the cookies for 18 minutes, or until done in the middle and golden brown around the edges.
Cool on parchment paper or foil. Once completely cooled, enjoy or store in plastic wrap lined cookie tins.