Preheat the oven to 350 degrees F (175 degrees C). Place an oven rack in the center position. Lightly grease a 9x13-inch baking dish.
Bake sweet potatoes in the preheated oven on the center rack until a knife inserted into the centers easily glides through, about 35 minutes. Let cool enough to handle, then peel and mash in a large bowl.
Add eggs, sugar, 1/4 cup butter, heavy cream, vanilla, cinnamon, and salt to mashed potatoes; mix well and transfer to the prepared baking dish.
Combine remaining 1/4 cup butter, brown sugar, pecans, and flour in a medium bowl. Mix with a pastry blender or your fingers to the consistency of course meal. Sprinkle over sweet potato mixture.
Bake in the preheated oven until topping is crisp and lightly browned, about 30 minutes.