Preheat oven to 375 degrees.
In a small bowl, combine cream cheese, sugar, vanilla, and flour. Set aside.
Open crescent roll dough and unroll, leaving crescents all together in one large rectangle
On an ungreased baking sheet, lay the crescent roll rectangle. The dough should be almost the entire length of a half sheet pan. (If you're not using a crescent roll sheet, be sure to press edges together to even out edges and seal any holes.)
Cut 1/2 inch diagonal strips up each side of the dough.
Carefully spread cream cheese filling down the center of the dough to be about 2-3 inches wide. Top with fresh blackberries or blackberry pie filling.
Fold 1/2 inch dough pieces up over filling alternating sides to get a braided pattern. You may have excess dough once you reach the end of the danish, so fold them in as best as you can.
Bake for 15-20 minutes or until filling is set and crescent dough is golden in color. Cool before removing from baking sheet.
Once danish has cooled, remove to serving platter.