This is based on a family recipe from my mother. The pecan crust lends a nice crunch to the yams, and the spices add a touch of refinement.
Place the butter in a heavy saucepan. Add the cream, sugar, pecans, salt, and spices and whisk until well combined. Bring to a boil over medium heat, reduce to a simmer, and cook for 5 minutes, stirring often. Remove from heat and add the vanilla extract.
Preheat the oven to 375 degrees.
Bring a large pot of salted water to boil over high heat. Add the yams and cook until soft. Remove from heat and strain completely. Place in a mixing bowl, add the butter, and beat with a whisk until smooth. Add the eggs and whisk again to incorporate.
Scald the milk in a saucepan: Bring it nearly to a boil over medium heat, stirring regularly, to keep the bottom from scorching. When bubbles start to form around the edges, remove from heat. Add the milk to the yams. Add the sugar and mix well. Transfer to a baking dish.
Pour the pecan praline over yam mixture and bake in the oven for 20 minutes. Use a cake tester to check for doneness. Serve hot.