Preheat and prepare pan

Preheat your oven to 350 °F (about 175 °C). Line a 9‑cup muffin tin with cupcake liners, then spray each liner lightly with cooking spray (or use a small dab of butter) to prevent sticking.

2. Make the Oreo crust

Place one Oreo cookie at the bottom of each liner (no need to crush them finely; a whole Oreo works nicely for a base in each mini pie). Set the pan aside.

3. Melt chocolate and butter

In a heatproof bowl, combine the 6 tablespoons of diced butter and 6 oz chopped chocolate. Set this bowl over a pot of simmering (or gently boiling) water, ensuring the bottom of the bowl does not touch the water. Stir until the mixture is completely smooth and melted. Be careful that no steam or water droplets enter the chocolate, as moisture can seize it. Remove from heat and allow it to cool slightly (but it should still be pourable).

4. Whip eggs and sugar

In the bowl of a stand mixer (or a large bowl with a hand mixer), add the 3 eggs, ¼ cup sugar, and a pinch of salt. Beat on medium (level 3 if your mixer has settings) for about 5 minutes, until the mixture becomes thick, pale, and aerated. This step is important to incorporate air and give the filling lightness.

5. Incorporate chocolate

With the mixer running on low, slowly drizzle in the melted chocolate mixture until fully combined. After adding it all, turn off the mixer and gently fold by hand to ensure everything is evenly incorporated — you want a smooth, uniform chocolate batter.

6. Portion into pans & bake

Using a ¼‑cup ice cream scoop (or tablespoon), divide the batter among the 9 prepared liners. You can fill them nearly to the top—they don’t rise much in the oven. Bake for about 15 to 18 minutes, or until the centers just jiggle slightly and a toothpick inserted comes out with a few moist crumbs (not fully clean). Remove from the oven and let them cool in the pan for a bit before transferring to a wire rack.

7. Make the ganache

While the pies cool, prepare the ganache. In a microwave‑safe bowl or measuring cup, combine ½ cup heavy cream and ½ cup chocolate chips. Microwave on high for 30–40 seconds. Then whisk until the chocolate is fully melted and smooth into the cream. Let it sit at room temperature until it thickens (about 1–2 hours). If you’re in a hurry, you can chill it briefly in the fridge—just watch it so it doesn’t become too firm.

8. Finish & serve

Once the ganache reaches a thick, spoonable consistency, spoon it generously over each mini mud pie. Let it set slightly before serving. Serve with a tall glass of cold milk or a dollop of whipped cream for extra indulgence.