01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving overhang on two sides for easy removal.
02 - Set a heatproof bowl over a saucepan of barely simmering water. Add the butter and chopped dark chocolate, stirring gently until completely melted and smooth. Remove from heat and let cool slightly.
03 - Whisk the sugar into the melted chocolate mixture until incorporated. Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract until fragrant and evenly distributed.
04 - Gently fold in the flour and salt using a spatula, mixing only until just combined. Avoid overmixing to keep the brownies tender and fudgy.
05 - Pour the batter into the prepared pan and spread into an even layer. Bake for 25–30 minutes, or until a toothpick inserted in the center comes out with moist crumbs attached. Do not overbake. Transfer the pan to a wire rack and let the brownies cool completely.
06 - Arrange the thinly sliced strawberries in a single even layer over the fully cooled brownie base, covering the entire surface.
07 - In a clean heatproof bowl set over simmering water, melt the semisweet chocolate with the coconut oil (or butter), stirring until glossy and smooth.
08 - Pour the melted chocolate over the strawberry layer, gently spreading with a spatula to cover evenly. 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 from the pan using the parchment paper overhang. Cut into 12 squares using a sharp knife warmed under hot water and wiped dry for clean, neat edges. Serve chilled or at room temperature.