Whisk together the sweetened condensed milk, egg yolks, key lime juice, lime zest, and a pinch of sea salt in a saucepan. Cook this mixture over medium-low heat, stirring regularly for 9-12 minutes, until it reaches 175°F. Transfer to a bowl and chill in the fridge while preparing the rolls.

Prepare the tangzhong by combining water and bread flour in a small saucepan. Heat this mixture over medium heat, whisking constantly for 4-5 minutes, until it thickens into a smooth paste. Set aside to cool slightly.

Mix the dry ingredients in a stand mixer by combining bread flour, granulated sugar, instant yeast, and fine sea salt. Add in the heavy cream, whole milk, large egg, and the cooled tangzhong. Knead on low speed for about 2 minutes until dough begins to form.

Incorporate the butter by adding one tablespoon at a time while mixing. Knead for an additional 8-10 minutes until the dough becomes smooth and elastic. Shape it into a round ball and let it rest for 30 minutes.

Combine the filling ingredients by mixing the brown sugar, softened butter, and ground cinnamon until smooth. Set this mixture aside as well.

Line a baking pan (9x13 inches) with parchment paper and lay graham cracker sheets across the bottom, creating a sweet base for your rolls.

Roll out the dough into a 15x21-inch rectangle on a lightly floured surface. Evenly spread the cinnamon sugar filling over the dough, followed by the chilled key lime filling, and top with crushed graham cracker crumbs.

Cut the filled dough into twelve 1 3/4-inch strips. Roll each strip tightly and place them into the prepared baking pan, laying them side by side.

Cover and rise the rolls, allowing them to sit for 1-2 hours until they double in size. Preheat your oven to 325°F/162°C during this time.

Bake the rolls for 30-40 minutes, or until they reach an internal temperature of 185°F and have a beautiful golden brown top.

Cool the rolls before making the frosting. In a bowl, mix the room temperature cream cheese and powdered sugar until creamy. Incorporate the remaining chilled key lime pie filling for a zesty frosting.

Frost the warm rolls generously with the cream cheese mixture and sprinkle extra graham cracker crumbs on top for that classic key lime pie touch. Enjoy this delightful treat!