Combine the milk and cream in a medium saucepan. Bring the mixture to a slow boil over medium heat, reduce the heat to low, and simmer for 30 minutes, stirring occasionally.
Combine the eggs and sugar in a medium bowl. Use a hand mixer on medium speed to beat until the mixture is thick, smooth, and pale yellow in color (similar to mayonnaise), about 2 minutes.
Reserve 1 cup of the hot liquid from step 1. With the mixer on low speed, add the cup of hot milk/cream to the egg mixture in a slow stream. When thoroughly combined, pour the egg mixture back into the saucepan and stir to combine. Cook, stirring constantly, over medium low heat until the mixture is thick enough to coat the back of a spoon.
Transfer to a bowl and fold in the instant coffee with a spatula or mixer on low until just combined.
Cover with a sheet of plastic wrap placed directly on the custard, and chill completely.
Pour into your ice cream maker and allow to churn for 20-30 minutes (or following manufacturer's instructions for your ice cream maker).
Transfer half of the ice cream to a freezer-safe container. Add half of the Oreo crumbs, chocolate chunks, fudge sauce, and pecans. Add the remainder of the ice cream and top with the remaining ingredients.