In a medium bowl, combine the boiling water and dark cocoa powder. Whisk until smooth and let it cool slightly.
In a separate bowl, combine the chopped dark chocolate and olive oil. Microwave in short bursts, stirring in between, until melted and smooth.
Add the cocoa mixture to the melted chocolate and olive oil. Mix well. Then, add the egg, egg yolks, and vanilla extract, stirring until fully incorporated.
Gradually add the sugar to the wet mixture, whisking until the mixture is glossy and well combined.
In another bowl, whisk together the all-purpose flour and salt. Gradually fold this dry mixture into the wet ingredients until just combined.
Gently fold in the chopped LINDOR truffles, ensuring they are evenly distributed throughout the batter.
Line a 9x9-inch baking pan with parchment paper, leaving some overhang for easy removal. Pour the brownie batter into the prepared pan, smoothing the top.
Preheat your oven to 350°F (175°C) and bake the brownies for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
As soon as the brownies come out of the oven, sprinkle the flaked sea salt on top. Allow the brownies to cool in the pan for about 15 minutes before lifting them out using the parchment paper.
Once cooled completely, cut into squares and serve. Enjoy the rich, indulgent flavors of your Olive Oil and Sea Salt Truffle Brownies!