Preheat the oven to 350°F/175°C.
Make the flax eggs. Mix the ground flaxseed meal with 5 tablespoons water, stir to combine and refrigerate for 15 minutes to thicken. Re-whisk the mixture again before using.
Prepare a double boiler. Add a few inches of water to a saucepan and bring to a simmer. Nestle a large heatproof glass bowl that sits on top of the saucepan without touching the water to create a double boiler.
Chop half of the dark chocolate (3 ounces or 85g) into bite-sized pieces and set aside.
Melt the chocolate and butter. Take the remaining half of the dark chocolate and roughly chop it or break it apart with your hands. Place these chocolate pieces and the vegan butter in the heat-proof bowl on top of the saucepan. Allow the chocolate mixture to melt, whisking frequently until smooth and the chocolate is completely melted. Set aside to cool.Alternatively, you can add the chocolate pieces and the vegan butter to a large bowl and microwave it. Melt in 25 second intervals until mostly melted and smooth, stirring well between each interval (3 total intervals should be good). While the chocolate-butter mixture is cooling, line an 8×8″ baking pan with parchment paper.
Mix the dry ingredients. In a medium bowl, whisk together the flour, baking powder, sea salt, and cocoa powder.NOTE: I recommend sifting the mixture, as cocoa powder can be lumpy. Mix the wet ingredients. Once the chocolate-butter mixture is cool, pour in the oil, plant-based milk, brown sugar, maple syrup, flax eggs, and vanilla. Whisk well until smooth and well combined.
Combine the dry and wet. Add the flour mixture into the liquid mixture and stir with a wooden spoon until just combined. Then fold in the reserved 3 ounces /85 g of dark chocolate pieces using a silicone spatula. Pour the batter into the lined pan and smooth out the surface out with a silicone spatula.NOTE: The batter should be rich and dense, but if it feels too thick or dry, add in 2 tablespoons of boiling water, 1 tablespoon at a time, stirring to combine until the batter is a bit looser. Bake the brownies. Bake for 20-25 minutes, or until a toothpick inserted in the middle comes out almost clean. I always check my brownies a few minutes before I think they’re going to be done. They may appear slightly under-baked, which means they're fudgy and rich, and they will continue to bake after you take them out of the oven. Transfer the brownies to a wire rack to cool for at least 30 minutes before adding the glaze.
Meanwhile, make the chocolate glaze. Whisk together the melted coconut oil, cocoa powder and agave nectar until smooth. Slice any large raspberries in half.
Top the cooled brownies with the chocolate glaze and spread evenly, using a spatula as needed. Top with all the raspberries. If you have any leftover glaze, drizzle it on top (I did so in the video). Place in the fridge to fully harden for at least 30 minutes.
For storage tips, see the note in the blog post called “How to store these brownies.”