Crock Pot Spinach and Artichoke Dip

2 8 ounce pkgs cream cheese
3/4 cup half and half
1 T. minced onion
1 clove minced garlic
1/2 cup Parmesan cheese
1 10 oz bag frozen spinach, thawed and well drained
1 13 oz can quartered artichoke hearts, rinsed, drained and chopped
2/3 cup Monterey Jack cheese, shredded (or mozzarella)
…..
Combine and cook in small crock pot on low for 2 hours.