In a large mixing bowl, cream together the sugar and butter until fluffy and creamy. Then, blend in the eggs and vanilla extract.

In a separate large mixing bowl, sift together the flour, baking powder, and salt.

Mix the dry ingredients into the wet ingredients a third at a time. Mix until all of the dry ingredients have been fully incorporated.

Fold the dried blueberries into the cookie dough.

The the cookie dough into heaping tablespoon sized balls. Line them up on a cookie sheet and allow them to chill the refrigerator for 2 hours or up to 4 days.

Preheat your oven to 350°F/175°C.

Place the blueberry sugar in a medium mixing bowl. Roll the tops of the cookies in the blueberry sugar. Use more sugar if necessary.

Place the sugar cookie balls on a cookie sheet lined with parchment paper, sugar sides facing up.

Bake at 350°F/175°C for 12 to 13 minutes or until lightly browned on the sides of the cookies and centers are soft.

Cool the cookies on a wire rack before serving.