Pre heat oven to 350℉ degrees. Line an 8*8 baking dish with parchment paper and lightly spray with cooking spray.
In a medium pan over low heat melt the butter until fully melted. Add in the Granulated sugar and mix until fully combined. Remove from heat, pour in a bowl and set aside to cool for a few minutes.
In a large bowl add in the eggs, water, vanilla, and brown sugar. Mix well.
Pour in the warm melted butter and sugar mixture and slowly stir until fully combined.
In a medium bowl sift together flour, unsweetened cocoa powder, baking powder, and salt. Fold in the dry ingredients until well combined.
Using a cutting board coarsely chop the Lindt chocolate into small pieces. Pour all but a big handful into the brownie batter and mix well.
Pour the batter into the lined baking dish and spread out evenly. Top with remaining chocolate.
Bake for 28-30 minutes. The brownies will have a flaky top and will look slightly firm to the touch.
Completely cool the brownies before slicing. Cool for 15 minutes in the baking dish. Pull up on parchment paper and allow brownies to finish cooling on a cooling rack or the counter.