First, preheat oven to 400°F. Line baking sheets with parchment paper. Next, whisk together flour, cocoa powder, baking soda, and salt. Set the bowl aside.
Then, in a large bowl, combine softened butter and confectioners’ sugar using a hand mixer. Beat until light and fluffy–one to two minutes.
Add the egg and vanilla to the creamed mixture, then mix for about 30 seconds.
While mixing on low, add the flour mixture to the creamed butter. Fold until just incorporated.
Tip: The dough is ready when most of it sticks to the paddle. When touched, it has a little give, but does not stick to fingers.
Next, on a floured surface, roll the chocolate cookie dough out into a ¼-inch layer. Dust the dough with flour if necessary, then cut the dough out with heart-shaped cookie cutters.
Place the chocolate cut out cookies onto the baking sheets, then bake them in the oven for seven to eight minutes. Allow the cookies to cool.
You can dip the cookies in hot chocolate and sprinkle them with all types of colorful sprinkles if you choose. These cookies are perfect for birthdays, Christmas, celebrations, Valentine's Day, and more!