Heat oven to 400 degrees F. Place yams on a baking sheet and roast 50 minutes or until they are just barely tender yet still hold their shape. Let cool completely at room temperature. (Can be made up to 2 days ahead.)

Remove skins from yams and cut yams into 1/2-inch-thick slices. Butter a 2-quart baking dish with 1 tablespoon of the butter. Arrange yam slices in dish, slightly overlapping. Heat oven to 375 degrees F.

Combine syrup, salt, pepper, and another 4 tablespoons of the butter in a small saucepan over medium heat until butter melts; whisk to combine. Pour mixture over yams.

In a small bowl, combine pecans, flour, sugar, and cinnamon; add remaining 3 tablespoons butter and rub in with fingers until mixture is evenly moistened and forms clumps; sprinkle over yams. Bake 35 minutes or until topping is browned.