Line a loaf pan with a parchment paper sling.
On low heat, slowly melt dark chocolate until it is completely smooth, continually stirring. Pour about 4 ounces of it into the bottom of the pan, creating a thin layer. (You should have about 2 ounces left to drizzle on the top.) Freeze for 5 minutes.
Meanwhile, melt white chocolate and sunflower seed butter over low heat, until completely smooth, continually stirring. Remove from heat. At same time, remove pan with dark chocolate from freezer.
Stir granola and sunflower seeds into white chocolate mixture, and spread with a spoon evenly onto chocolate layer. Press down a bit to compact. Then drizzle remaining dark chocolate on top. Freeze for 15 minutes until completely set. Slice in 1/2 inch portions and enjoy. Refrigerate leftovers for up to two weeks.