In a food processor fitted with a metal blade, process the cream cheese, cream, Parmesan cheese, and garlic powder until smooth and creamy. Add the spinach and process until thoroughly mixed. Add the artichokes and process just until coarsely chopped.
Turn the mixture into a 3 1/2-quart crockpot; smooth the top. Cover and cook on the HIGH heat setting 1 1/4 to 1 1/2 hours, until hot in the center.
Sprinkle the top evenly with the jack cheese and spoon the salsa in a ring around the inside edges of the crockpot. Cover and continue heating on HIGH 15 minutes longer, or until the cheese is melted.
Reduce the heat to the LOW setting and serve warm with crackers or tortilla chips for dipping. Refrigerate any leftovers.Servings: 10