Preheat oven to 350°F (175°C). Process cookies into fine crumbs in a food processor. Mix with melted butter, optional sugar, and salt until it resembles wet sand.

Press mixture firmly and evenly into a 9-inch tart pan with removable bottom. Bake for 10-12 minutes until set. Cool completely on a wire rack.

Place chopped chocolate in a heatproof bowl with a fine-mesh sieve set over it. In a saucepan, heat cream and espresso powder over medium until steaming and powder is dissolved.

Pour hot cream through sieve over chocolate. Let sit 2-3 mins, then whisk from center out until smooth and glossy. Whisk in optional corn syrup.

Whisk in room temperature butter pieces until fully incorporated and ganache is silky. Whisk in sea salt.

Pour warm ganache into cooled crust. Tap gently to release bubbles. Refrigerate for at least 4 hours, or overnight, until completely set.

Before serving, remove tart ring. Garnish with cocoa powder, espresso beans, or whipped cream as desired. Slice with a hot knife to serve.