Cream together the butter or sunflower spread and caster sugar until light and fluffy.
Add the honey, eggs, and vanilla bean extract. Mix well.
Pour in the flour and oats and mix well.
Line a square baking tin (approx 20 cm) with baking paper. Preheat the oven to 180 degrees (fan).
Spoon half the oaty mixture into the tin and spread into an even layer.
Mash half of the blackberries in a small bowl with the back of a fork until you have a runny consistency.
Spoon the mashed blackberries over the oaty mixture and spread around using the back of the spoon.
Roughly spoon the rest of the oaty mixture over the blackberry layer and spread it gently.
Scatter the remaining (whole) blackberries on top and press them in gently.
Bake for 25 to 30 minutes or until golden brown on top and cooked through (check with a skewer).
Allow to cool and then slice into squares and enjoy.