Preheat your oven to 350°F. Crush your Oreos (cream included!) into fine crumbs. Mix in the melted salted butter until the crumbs feel like damp sand. Press the mixture firmly into the bottom and up the sides of your 9 inch (springform pan or pie dish with removable bottom). Tip: pressing with the bottom of a glass makes a nice, even surface. Bake for around 11 minutes, then let it cool completely so it’s ready to hold your chocolatey filling.

Add both the whole milk and heavy cream to a small saucepan. Warm it gently over low heat until it feels pleasantly warm to the touch, just cozy, not boiling. This gentle heat helps create a perfectly smooth mousse.

In a mixing bowl, whisk together the egg yolks, sugar, and the optional pinch of espresso. Slowly add the warm milk and cream, a little at a time, whisking constantly. Take your time here; it keeps the eggs from curdling and ensures your mousse will be silky.

Return the mixture to the pan and cook gently over medium-low heat, stirring often. You want it to thicken just a little and become glossy and creamy, this is the first glimpse of that dreamy chocolate texture.

Remove from heat and stir in the chopped dark chocolate and butter. Let it rest for a minute, then whisk until everything is smooth and melted together. Mix in the vanilla extract, and go ahead, taste a little to make sure it’s perfect.

For an ultra-smooth finish, you can give it a quick spin with an immersion blender for 30–45 seconds. This makes the mousse extra creamy and luxurious.

Pour the chocolate filling into your cooled Oreo crust, smoothing the top with a spatula. Chill in the fridge for at least 6 hours; overnight gives the best set. Good things take time, and this pie is no exception!

Using a mixer, whip the chilled cream with sugar and vanilla until it thickens into stiff, airy peaks. Start slowly, then increase speed to get fluffy, stable cream without over-whipping. Spread or pipe it over the chilled pie for a beautiful topping.

Slice with care, serve, and savor every bite, a little sneak taste before anyone else sees it is highly recommended! Sprinkle some crushed Oreos on top if you want a little extra crunch and decoration.