Preheat your oven to 375 degrees and line an 8-inch square pan with parchment paper.
In a bowl, stir together the maple syrup, cornstarch, vanilla and lemon juice. Then mix in the blueberries and set it aside.
In a separate bowl, stir together oatmeal, oat flour, coconut sugar, baking powder and salt. Then stir in apple sauce followed by the coconut oil. The dough will be crumbly. Cut the dough in half and press half of the dough into the bottom of the prepared pan.
Pour the blueberry mix evenly over the crust and stir in poppy seeds into the remaining mixture of dough, and then crumble over the berry layer.
Bake in oven for 40 minutes, or until top crumbled pieces are slightly brown. Cool for about 20 minutes and serve.