Preheat the oven to 180C/350F. Line a 6 x 6-inch square pan with parchment paper and set aside.
In a large mixing bowl, cream the butter with the brown sugar. Add the egg (or flax egg) and molasses and vanilla extract, until glossy. Gently add in the dry ingredients and mix until combined. Fold through the white chocolate chunks.
Transfer your batter into the lined pan and bake the blondies for 20-25 minutes, or until the tops are just tender.
Remove the blondies from the oven and let them cool completely, before slicing and serving.
TO STORE: Leftovers can be stored at room temperature, covered, for up to one week. If you'd like them to keep longer, store them in the refrigerator for up to two weeks. TO FREEZE: Place leftovers in an airtight container and store it in the freezer for up to 6 months.