Ingredients:

  • 3 lbs sweet potatoes, peeled and cut into 1-inch chunks
  • 1/2 cup (1 stick) unsalted butter, melted, plus extra for greasing
  • 1/2 cup packed dark brown sugar
  • 2 large eggs, lightly beaten
  • 1/4 cup milk or evaporated milk
  • 1 tablespoon vanilla extract
  • 1 teaspoon ground cinnamon
  • 1/2 teaspoon ground nutmeg
  • 1/2 teaspoon salt
  • 1/2 cup all-purpose flour
  • 1/3 cup packed dark brown sugar
  • 1 cup chopped pecans
  • 1/4 cup cold unsalted butter, cut into small cubes
  • Optional: 1 cup mini marshmallows

Instructions:

  1. Cook the Potatoes: Place the peeled and cubed sweet potatoes in a large pot. Cover with water and a pinch of salt. Bring to a boil and cook until fork-tender (about 20-25 minutes).
  2. Drain and Mash: Drain the potatoes thoroughly. Transfer them to a large mixing bowl. Mash the potatoes until smooth, using a masher or a handheld mixer for a creamier finish.
  3. Combine Wet Ingredients: In a separate small bowl, whisk together the melted butter, brown sugar, eggs, milk, vanilla extract, cinnamon, nutmeg, and salt until well combined and smooth.
  4. Mix the Casserole Base: Pour the wet mixture over the mashed sweet potatoes. Stir vigorously until the mixture is uniform, creamy, and lump-free. Taste and adjust sugar/spice if necessary.
  5. Prepare the Slow Cooker: Lightly grease the interior of the 6-quart slow cooker with butter or use a slow cooker liner for easy clean-up.
  6. Load the Cooker: Transfer the sweet potato mixture into the slow cooker, levelling the top with a spatula.
  7. Cook (Phase 1): Cover the slow cooker and cook on LOW for 3 to 3.5 hours. Do not lift the lid during this time. The casserole should be hot all the way through and slightly set around the edges.
  8. Make the Streusel: While the casserole is cooking, prepare the topping. In a medium bowl, combine the flour, brown sugar, and chopped pecans.
  9. Cut in the Butter: Add the cold, cubed butter. Using your fingers or a pastry blender, rub the butter into the dry ingredients until the mixture resembles coarse, pea-sized crumbs.
  10. Add Topping and Finish: After 3 hours of cooking, sprinkle the streusel mixture evenly over the top of the hot sweet potato base. Change the setting to HIGH.
  11. Cook (Phase 2): Cook uncovered (if possible) or covered slightly ajar on HIGH for 30 minutes, or until the streusel is lightly browned and crunchy. If using marshmallows, sprinkle them on top during the final 15 minutes.