I have always tended to cook and bake by using what I have on hand. A little bit of this and a little bit of that. I've been doing that for years. I actually measured this time for everyone so I could post the recipe for you. Feel free to modify to whatever your personal tastes are.
In a medium bowl combine:
1 package softened cream cheese
2 cup mozzarella cheese, shredded
1 cup Parmesan Cheese, shredded
2 teaspoons Worcestershire Sauce
2 teaspoons Italian Spice Blend OR Epicure's Foccacia Spice
1/2 cup Sour Cream
3 cloves garlic, minced
1 medium red onion, diced fine
1 medium red pepper, diced fine
4 cups baby spinach, chopped
pepper to taste
Mix altogether and smooth down into an ungreased baking dish. I used my round casserole dish. Bake at 325F for 30 minutes. Remove from oven and allow to cool for a bit. Serve with crackers, pita chips or carrot sticks.