Preheat oven to 350F (180C). Line a 9-inch (2.5 L) square baking dish with parchment paper, allowing excess paper to hang over each side.

In a food processor or high-speed blender, combine the dates, banana, maple syrup, almond butter, hazelnut oil, and vanilla. Process until smooth with flecks of dates still visible.

In a large bowl, mix together the oats, cocoa powder, and salt.

Stir the date mixture into the oat mixture until well combined, then stir in the hazelnuts, cacao nibs, and hemp hearts until evenly combined with crunchy bits strewn throughout. Press the mixture evenly into the baking dish. Bake for 30-35 minutes or until the edges start to lightly brown. Let cool completely before removing from the dish and cutting into 16 bars.

To make the chocolate drizzle, place the chocolate in a heatproof bowl and place it over a small saucepan filled with 1 inch of water. Bring the water to a bare simmer and let the chocolate gently melt, stirring often.

Using a fork, drizzle the chocolate over the bars and sprinkle with the minced hazelnuts. Allow the chocolate to set before eating or storing.