Whisk together the gluten free flour blend, cocoa powder, baking powder, and fine sea salt in a medium bowl. Set aside.
In a large bowl, beat the softened butter and granulated sugar with an electric mixer on medium-high speed until light and fluffy, about 3 minutes. Beat in the egg, red food coloring, vanilla extract, and white vinegar until the color is vibrant and even throughout.
Add the flour mixture and mix on low speed until just combined into a soft dough. Cover the bowl tightly and refrigerate for at least 2 hours or overnight until the dough is very firm.
Preheat the oven to 350 degrees F and line two baking sheets with parchment paper. Place the powdered sugar in a small shallow bowl.
Scoop the chilled dough into 1-tablespoon balls and roll each one generously in the powdered sugar until thickly coated on all sides. Place them about 2 inches apart on the prepared baking sheets.
Bake for 10 to 12 minutes until the tops are puffed and crackled with beautiful red peeking through the white powdered sugar coating. The centers should still feel soft when gently touched.
Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. The cookies will be fudgy and soft inside with a dramatic crinkle coating.