Combine the cream cheese, sour cream, artichoke hearts, and spinach in the crockpot insert.

Stir in half of the mozzarella, saving the rest for the top.

Cover and cook on low for 2 hours, stirring once halfway through, until the cream cheese has fully melted into the sour cream with no lumps.

Sprinkle the remaining mozzarella over the top.

Cover and cook for another 15 minutes, until that top layer is melted and the dip is bubbling gently at the edges.

Switch to the warm setting and stir once before serving, scraping the sides where the dip cooks fastest.

Serve directly from the crockpot with sturdy chips or sliced baguette, since the dip loosens as it sits and chips closer to room temperature.