Shake Shack Burger with Spinach Artichoke Sauce

Ingredients

• 8 oz cream cheese, softened at room temperature
• 1/3 cup mayonnaise
• 2 tbsp ketchup
• 2 tbsp mustard
• 1/2 tsp salt
• 1/4 tsp ground black pepper
• 1/4 cup frozen chopped spinach, thawed & squeezed
• Reese Quartered Artichoke Hearts, drained
• 1 pound ground beef, divided into 4 portions
• 1 tsp salt
• 1/4 tsp black pepper
• 4-8 slices american cheese
• 1 large tomato, sliced
• 4-6 green lettuce leaves
• 4 burger buns, toasted