Preheat an oven to 350 degrees and line a sheet pan with parchment paper. Spread the hazelnuts out evenly. Bake 8-10 minutes on the lower rack until fragrant, being careful not to burn them. Leave the oven on at 350 degrees for the next steps.

While the hazelnuts are roasting, grind the almonds into a flour in a food processor. It should only take a minute or two. Add the almond flour to a large bowl with the salt, baking powder, cocoa and stir well.

Once the hazelnuts are finished roasting, add only 1 cup of them to a food processor. Pulse for a few minutes, scraping the sides as necessary, until a paste forms. Add the syrup and vanilla and pulse again until it becomes very creamy and smooth. Do not stop too early, it should be smoother than almond butter. Add the mixture to the dry ingredients of the bowl and stir well, it will be very thick.

Line an 8X8 square baking pan with parchment paper going in both directions for easy removal later. Add the batter to the pan, place a sheet of parchment paper over it and press the mixture flat and out to the edges with your hands. Start from the center and work your way around. Even if it seems there isn't enough dough, keep pressing the mixture around evenly. You can also use a pastry roller over the paper to get it smooth and flat. I slightly dampened my fingertips to press the dough along the edges. Bake on the middle rack for 10 minutes.

While the dough is baking, prepare the 2nd layer of hazelnut chocolate. Add another cup (the remaining 1/4 will be for garnish) of the roasted hazelnuts to the food processor and again, pulse until very creamy and smooth. Do not stop at the thick paste stage, keep going, and scrape the sides as needed. After a few minutes it will become silky smooth. Once it's smooth, add the sugar (if using). Taste and add another tablespoon if you want it slightly sweeter. In a small bowl, add the hazelnut butter, chocolate chips and stir together.

Pour over the pre-baked bottom layer and spread out. Doesn't have to be perfect because it will be melted when baked. Bake for 10 mins. Remove and spread the melted chocolate hazelnut all over the bottom layer. Place the reserved 1/4 cup hazelnuts and raspberries evenly all over the melted chocolate. Chill in the fridge to set and firm up for 1-2 hours before slicing. Mine took 1 1/2 hours. Keep stored in the fridge.