In a medium saucepan, melt butter over medium-high heat. Add onion and garlic. Cook for 3 minutes. Add spinach; cook 3-5 minutes or until onion is tender and the spinach is cooked, stirring frequently. Remove from heat.
Stir in chopped artichoke, cream cheese, mayonnaise, Swiss cheese, Parmesan cheese and hot pepper sauce.
Transfer to an ungreased 1 1/2 quart casserole. Bake for 40 minutes. Top with pecans; bake and addtional 10 minutes. Makes 4 cups.