Place lemon juice, sugar, coconut water, and water into a pitcher and shake or stir vigorously until all the sugar is dissolved. I prefer to shake because it aerates the lemonade and makes a nice head on top.
Pour 1/2 of the lavender syrup into the pitcher and stir. You can add more or less lavender syrup to your personal taste. I personally find that 1/2 of the lavender syrup recipe is a good balance.
Preheat the oven to 325F and cover an 8 x 8 pan with tinfoil, buttered. Place the pan on a baking sheet.
In a bowl set over a double boiler, melt the chocolate and butter. Keep the heat low so that the butter doesn’t separate. Remove from the heat when the chocolate is melted. Whisk in the eggs, one at a time, combining thoroughly. Whisk in the rhubarb puree and vanilla and then give an extra whisk to bring it all together. Switch to a spatula and fold in the urfa-biber and flour. Continue to fold the ingredients together and add the Armagnac and raisins. Pour the batter into the pan and bake for 34-38 minutes. The brownies will still be a little wet in the middle but dry on the outer edges. Place on a rack to cool.