Butter a 9 X 13 Casserole. Slice french bread into approx. 20 slices. Mix remaining ingred. until well blended but not too bubbly. Dip each slice of bread in the milk mixture and overlap in casserole in a semi-standing position. (Not Flat) Pour remaining milk mixture over bread. Cover and refrigerate overnight. Add 1 T vanilla to milk mixture if you like.
Prepare topping: 1 Cup chopped pecans; 1/2 Cup softened butter; 2 T light Karo syrup; 1/2 tsp cinnamon; 1/2 tsp nutmeg; 1 Cup packed light brown sugar. Mix all ingredients and spread over the top of the French Toast. Bake for 45 minutes @ 350 until raised and golden brown. If cooked longer, it will still be great, just not as custardy.