Preheat the oven to 180°C and line a 20 x 20 cm baking pan with parchment paper.
Melt the butter and cook it on medium heat until it gets brown and smells nutty, around 10 minutes. Be careful not to overcook the butter and burn it. Brown not black!
In a bowl mix together the browned butter, sugar, eggs and vanilla extract.
Mix in 100 g of melted chocolate, then add the flour and salt, mix well, until the batter pulls away from the bowl.
Fold in the ruby chocolate chips.
Spread the batter in the prepared pan and bake for about 25 minutes. If you insert a toothpick or a knife into the batter it should have a few moist crumbs attached to it, as we don't want to over bake and have our blondies still ooey gooey!
Melt the 100 g of ruby chocolate and drizzle over the blondies. Cut in squares.
Let the blondies cool down.