Roughly chop the chocolate and place in a large heatproof bowl.
In a small bowl lightly beat the eggs.
In a small saucepan mix together cream, espresso powder, and salt over medium heat until it comes to a simmer. Be sure to stir to keep from scorching the cream.
Pour the cream mixture into the bowl with chocolate. Allow to rest a minute and begin stirring until the chocolate and cream mixture have incorporated. Add the butter and continue to stir until fully incorporated. Pour the eggs through a fine mesh strainer and continue to stir until it’s completely mixed and glossy.
Pour the mixture into the tart crust and shake gently to evenly distribute the mixture.
Bake the tart on a baking sheet for 30-35 minutes, until there are faint cracks on the outer edge of the filling.
Leave on the baking sheet and allow to cool completely on a wire rack.
Remove the outer ring of the tart pan. Use a thin metal spatula to loosen the tart and slide it on a serving platter (the parchment paper should help).
Garnish with chocolate curls.
Cut into wedges and serve.