Preheat the oven to 400°F/200°C/Gas 6. Lightly grease a 3-quart (2.8L) casserole dish and set it aside.
While the oven is preheating, heat a large pot of lightly salted water over high heat and prepare the pasta according to package directions, cooking 1-2 minutes less than al dente. (Pasta will continue to cook during baking).
When the pasta is finished cooking, reserve one-half cup of the cooking liquid and set it aside. Drain the pasta but do not rinse. Return the pasta to the cooking pot. Add the reserved cooking water, milk, heavy cream, and cream cheese. Stir gently until the cream cheese melts.
Add the baby spinach, artichokes, and cheddar cheese. Stir to combine. Add salt and black pepper, to taste.
Transfer to the prepared casserole dish.
In a small bowl, stir together the panko, melted butter, garlic powder, and fresh parsley. Sprinkle the panko topping over the casserole.
Bake in the preheated oven for 10-15 minutes until the pasta is hot and bubbly and the topping is golden brown. Enjoy!