In a large food processor, process cream cheese, lemon zest, lemon juice, and creme faiche until smooth. Slowly add milk, cream, and sugar. Process until smooth.
Transfer mixture to an airtight container. Store in fridge and let mature overnight.
Preheat oven to 350 degrees. Toss sliced bananas in a bowl with brown sugar, melted butter, and salt. Spread bananas out on parchment lined baking sheet. Bake for 20-25 minutes until bananas have softened and sugar has begun to caramelize. Remove from oven and transfer bananas and any liquids into another container. Allow to cool to room temperature. Store in the fridge until ready to use
Graham Cracker Crumbs:
Preheat oven to 350 degrees F. In a small bowl, combine ground crackers, salt, and melted butter. Spread on a parchment lined baking sheet. Bake for 8-10 minutes until toasted. Crumbs with crisp up as they cool.
Churn ice cream base according to ice cream maker according to your unit's instructions. Once the volume has increased by half and mixture has reached a soft serve consistency, add roasted bananas. If necessary, break up cold roasted banana into chunks before dropping to into ice cream maker.
Once bananas have been distributed, transfer mixture into an airtight container and let harden in the freezer for at least 45 minutes before serving.
Serve ice cream with cooled graham cracker crumbs.