Grease a 9x9 baking dish with butter. Dust with flour and tap out the excess.
Melt the butter and chocolate in a small saucepan over low heat, stirring frequently. Remove from the heat and let cool to room temperature.
Meanwhile, beat the eggs, sugar, and vanilla until smooth. Add the cooled chocolate mixture and mix until well combined. Stir in the nuts.
Measure the flour and salt and then sift directly onto the chocolate mixture. (I don't sift anything, so I just gave them a stir and then sprinkled it on the top of the chocolate mixture.) Mix until well combined and no trace of the dry ingredients remains.
Pour half of the batter into the prepared baking pan and spread it out to reach the edges. Place the pan in the refrigerator while you make the caramel sauce.
Unwrap the caramels and place them in a microwaveable bowl with the water. Microwave on medium powder and check every 50 seconds or until the caramels have melted into a thick liquid. Let cool for 5 minutes. Whisk the caramel with a fork to get a consistent texture. Pour the caramel over the batter in the pan. Don't go all the way to the edges and don't worry about covering every spot. Place the pan back in the refrigerator for 20 minutes to allow the caramel to set.
Remove the pan from the fridge and spread the remaining half of the batter evenly over the caramel using a spatula. Let the pan sit for 15 minutes to come to room temperature.
Pre-heat the oven to 350 degrees. Bake for 35 minutes or until the brownies begin to pull away from the sides of the pan.
Cool on a wire rack for 1 hour before serving.