Preheat oven to 350F.
Butter the bottom of an 8x8 inch baking pan.
In a large bowl, combine the oats, brown sugar, baking powder, cinnamon and salt.
In a medium sized bowl, whisk together the egg, milk oil and vanilla.
Pour the wet ingredients into the dry ingredients and stir to combine.
Arrange half of the blackberries in the baking dish.
Spoon in the oatmeal mixture.
Press the remaining blackberries into the top of the oatmeal mixture.
Bake at 350F for 30-40 minutes, or until the middle is set and the edges are golden brown.
Drizzle with honey and cinnamon to serve.