Boil sweet potatoes: Place cubed sweet potatoes in a large pot, cover with cold water, and bring to a boil. Reduce heat and simmer for 15-20 minutes, or until tender. Drain well.

Mash sweet potatoes: While still hot, mash sweet potatoes thoroughly using a potato masher or electric mixer.

Combine wet ingredients: In a large bowl, whisk together melted butter, heavy cream, eggs, vanilla, cinnamon, nutmeg, cloves, salt, and sugar until well combined.

Add to sweet potatoes: Pour wet ingredients into mashed sweet potatoes and mix until fully incorporated.

Make topping: In a medium bowl, combine flour and brown sugar. Cut in cold butter using a pastry blender or your fingers until mixture resembles coarse crumbs. Stir in pecans and milk until just combined.

Assemble and bake: Pour sweet potato mixture into a greased 9x13 inch baking dish. Sprinkle topping evenly over sweet potatoes.

Bake: Bake in a preheated oven at 350°F (175°C) for 30-35 minutes, or until topping is golden brown and casserole is heated through.

Cool slightly: Let cool for a few minutes before serving.