01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving enough overhang on the sides to lift the brownies out later.
02 - Combine the unsalted butter and chopped dark chocolate in a heatproof bowl set over a saucepan of barely simmering water. Stir gently until completely smooth and glossy. Remove from heat and let cool slightly for about 2 minutes.
03 - Whisk the granulated sugar into the melted chocolate mixture until well blended. Beat in the eggs one at a time, mixing thoroughly after each addition. Stir in the vanilla extract until the batter is smooth and uniform.
04 - Gently fold the all-purpose flour and salt into the batter using a spatula. Mix only until just combined—overmixing will produce a dense, tough crumb.
05 - Pour the batter into the prepared pan and spread it into an even layer. Bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out with moist crumbs clinging to it. Do not overbake. Transfer the pan to a wire rack and let the brownies cool completely.
06 - Once the brownie base is fully cooled, arrange the thinly sliced strawberries in an even, single layer across the entire surface, ensuring full coverage from edge to edge.
07 - Melt the semisweet chocolate chips together with the coconut oil (or butter) in a heatproof bowl set over simmering water, stirring until the mixture is silky smooth and pourable.
08 - Pour the melted chocolate coating evenly over the strawberry layer, gently spreading with a spatula to seal the edges. Refrigerate the pan for at least 1 hour, or until the chocolate shell is fully set and firm to the touch.
09 - Lift the brownies out of the pan using the parchment paper overhang. Run a sharp knife under hot water, dry it, and cut into 12 squares for clean, smooth edges. Serve chilled or at room temperature.