Preheat the oven to 400°F. Wash the sweet potatoes and prick them a few times on all sides with a fork. Place them on a parchment or foil lined baking sheet and bake in the oven for 70-80 min. Once they are fork tender, remove them from the oven and let them cool. Then lower the oven temp to 350°F.
Once the sweet potatoes have cooled down, peel off the skin and transfer the potatoes to a large bowl. Mash them with a potato masher or fork. Or blend them for a few seconds with a hand mixer to break up the stringy pieces for a smoother texture.
Now in a separate bowl whisk the butter, both sugars, vanilla extract, cinnamon, nutmeg, salt, half and half, and the eggs together until well combined.
Combine the wet ingredients with the sweet potatoes and blend with the hand mixer until smooth.
Pour the sweet potato mixture into a medium size buttered baking dish. I used an 11x7-inch baking dish, but any medium size oven-safe dish will work.
Next, make the topping. In a small bowl combine the chopped pecans, brown sugar, and cinnamon. Mix them together with a spoon or your hand and break up any large clumps of sugar. Then add the melted butter and stir to combine.
Sprinkle the pecan mixture over the sweet potatoes. Bake in the oven at 350°F for 30 minutes. The sides will be bubbly and the pecans will be golden brown. Serve warm and enjoy.