Crush the chocolate sandwich cookies in a food processor. Mix with melted butter and press into a 9-inch pie pan. Freeze while preparing filling.
In a heavy-bottomed saucepan, heat cream, milk, sugar, cocoa powder, and coffee powder until steaming. Whisk egg yolks in a bowl, then slowly temper with hot mixture. Return to pan and cook until slightly thickened. Strain, stir in chocolate chips until melted, then vanilla extract. Chill completely.
Churn ice cream base in an ice cream maker. Spread half into prepared crust, swirl in hot fudge, top with remaining ice cream. Cover with plastic wrap and freeze at least 4 hours. Top with whipped cream, mini chocolate chips, and chopped pecans before serving.
Notes
For an extra kick, you can increase the instant coffee powder to 1 ½ teaspoons. The dessert is rich, so small slices go a long way!