Preheat your oven to 350°F (175°C). Stir the melted butter together with the Oreo crumbs, salt, and sugar until evenly combined. Press the mixture firmly into five tart pans (about 4" size). Bake for 8 minutes, then let cool completely.

In a saucepan over medium heat, melt the sugar—stir often until it's fully liquid and amber in colour. Immediately stir in the butter until melted, then whisk vigorously until smooth. Slowly pour in the cream while stirring. Let the mixture boil for 1 minute, then remove from heat and stir in the salt. Set aside to cool.

Heat the cream until just steaming, then pour it over the chopped chocolate. Let sit for 2–3 minutes, then stir until smooth. Add the butter, espresso powder, salt, and vanilla, and stir until glossy and well combined.

In a stand mixer, whip the cream with sugar, vanilla, and espresso powder until stiff peaks form.

Once the tart shells have cooled, spoon or pipe a layer of salted caramel into the bottom of each one.

Pour or pipe the ganache over the caramel, filling each tart shell.

Let the tarts set in the fridge until firm, about 1–2 hours.

Pipe the espresso whipped cream on top.

Optional: use extra ganache or caramel to drizzle over the top for a dramatic finish.