Preheat your oven to 325°F and lightly grease a 9x13 inch baking dish (or similar size casserole). While the oven heats, remove your eggs and cream cheese from the refrigerator—room temperature eggs will blend more smoothly into the creamy mixture, creating a better texture. Measure out all your spices into a small bowl for easy adding, and have your cooked chicken ready.

In a blender or food processor, combine the room temperature eggs, softened cream cheese, sour cream, and cottage cheese. Add the measured spices from Step 1 and blend on medium speed until completely smooth, about 30-45 seconds. The mixture should be creamy with no lumps—I like to scrape down the sides halfway through blending to ensure everything is fully incorporated. This smooth, custard-like base is what makes this casserole so luxurious.

Spread the 2.5 cups of cooked chicken evenly across the bottom of the greased baking dish. Scatter the 1.25 cups of mozzarella cheese over the chicken layer. This arrangement ensures the cheese melts into and around the chicken pieces as the casserole bakes, creating pockets of flavor throughout.

Pour the creamy custard base from Step 2 evenly over the chicken and cheese layer, making sure it reaches all corners of the dish. The liquid will settle and distribute around the chicken as it bakes. Place the dish in the preheated 325°F oven and bake for 50 to 60 minutes, until the top is golden and set but still slightly jiggly in the very center (it will continue to set as it cools). For even cooking, I rotate the dish halfway through if your oven has hot spots.

Remove the casserole from the oven and let it rest for 5 to 10 minutes before cutting or serving. This resting time allows the casserole to set up completely and makes it easier to portion without everything falling apart. The carryover cooking during this rest also ensures it's fully set throughout.