Preheat the oven to 375°F and grease a 9 inch baking dish.

Beat the softened cream cheese, sour cream and mayonnaise together with a hand mixer on medium speed for 1 minute, until smooth.

Squeeze the thawed spinach over the sink with your hands until no more water drips out; this keeps the finished dip from turning watery.

Fold the squeezed spinach, chopped artichokes, garlic, 3/4 cup of the mozzarella, the Parmesan, salt and pepper into the cream cheese mixture, until evenly combined.

Spread the mixture into the prepared dish and smooth the top, then scatter the remaining 1/4 cup mozzarella over the surface.

Bake for 22 to 25 minutes, until the top is golden brown in patches and the center is set but still soft when pressed with the back of a spoon.

Let the dip rest for 5 minutes before serving; it continues to firm up slightly as it cools.

Serve warm, straight from the baking dish, with toasted baguette slices or pita chips alongside for scooping.