1. Preheat your oven to 350°F (175°C). Grease a 9-inch tart pan with a removable bottom.

2. In a medium saucepan, heat the heavy cream over medium heat, stirring occasionally, until it just begins to simmer.

3. Remove the pan from the heat and add the chopped dark chocolate. Let the chocolate sit for 2-3 minutes, then whisk the mixture until the chocolate is completely melted and the ganache is smooth.

4. Add the softened butter and whisk until fully incorporated.

5. In a separate bowl, whisk together the eggs, sugar, vanilla, and salt until well combined.

6. Slowly pour the egg mixture into the chocolate ganache, whisking constantly, until the filling is smooth and homogeneous.

7. Pour the chocolate filling into the prepared tart pan and use a spatula to spread it evenly.

8. Bake the tart for 20-25 minutes, or until the center is just set. Allow the tart to cool completely in the pan, then carefully remove the outer ring.

9. Just before serving, gently apply the edible gold leaf flakes to the top of the tart, creating an elegant, shimmering finish.

10. Slice and serve the Dark Chocolate Tart with Gold Leaf, enjoying its rich, velvety texture and luxurious presentation.