In a saucepan over medium heat, whisk together milk, cocoa powder, and sugar until warm and fully combined.

1. In a separate bowl, beat egg yolks, then slowly temper with the warm chocolate mixture. Return to the saucepan and cook until slightly thickened.
2. Remove from heat, add chopped chocolate and vanilla extract. Stir until smooth. Stir in heavy cream. Chill thoroughly in the refrigerator.
3. Churn in an ice cream maker according to the manufacturer’s instructions. Transfer to a container and freeze until firm.
4. Preheat oven to 350°F (175°C). In a large bowl, cream together peanut butter, softened butter, brown sugar, and granulated sugar until light and fluffy.
5. Beat in eggs and vanilla extract. Mix in flour, baking soda, and salt until fully incorporated.
6. Scoop dough onto a baking sheet and flatten with a fork. Bake for 10–12 minutes or until golden. Let cookies cool completely.
7. Allow chocolate ice cream to soften slightly. Scoop and spread onto the flat side of one cookie, then top with another cookie and press gently.
8. Smooth edges if desired, then freeze sandwiches until firm before serving.