Preheat oven to 350 degree F. In a medium saucepan, melt butter over medium-high heat. Add onion and garlic; cook for 3 minutes. Add spinach; cook for 3 to 5 minutes more or until onion is tender and spinach is cooked, stirring frequently. Remove from heat. Stir in chopped artichoke hearts, cream cheese, mayonnaise dressing, cheddar cheese, Parmesan cheese, and hot pepper sauce.
Transfer to an ungreased 1-1/2-quart casserole. Bake for 40 minutes. Top with pecans; bake for 10 minutes more.
Serve with toasted bread slices. Makes 4 cups spread (sixty-four 1-tablespoon servings).