1-First Step: Prepare the sweet potatoes
Peel 4 pounds of sweet potatoes and cut into 1-inch cubes. This even size ensures quick, uniform cooking. Place in a large pot, cover with cold water by 1 inch, and add a pinch of salt. Bring to a boil over high heat, then reduce to medium and simmer 20-25 minutes until fork-tender. Drain well in a colander and let steam escape for 2 minutes to avoid watery mash.

2-Second Step: Mash the base
Transfer hot sweet potatoes to a large bowl. Use a potato masher or fork for a slightly chunky texture, or immersion blender for ultra-smooth. Mash until mostly smooth, then cool slightly for 5 minutes. This prevents curdling when adding eggs.

3-Third Step: Mix in wet ingredients
Stir in ½ cup melted butter until fully incorporated. Add 1 cup brown sugar, 2 beaten eggs, ½ cup milk, 1 tsp vanilla, and ½ tsp salt. Beat with a wooden spoon or mixer on low for 1-2 minutes until creamy and uniform. Taste and adjust salt if needed. The mixture should be thick like pudding.

4-Fourth Step: Spread into baking dish
Pour the sweet potato mixture into your greased 9×13-inch dish. Smooth the top with a spatula for even baking. Set aside while you make the topping. Wipe any spills for a clean bake.

5-Fifth Step: Combine dry topping ingredients
In a medium bowl, mix 1 cup chopped pecans, 1 cup brown sugar, and ⅓ cup flour. Use your fingers to break up sugar clumps. This dry mix sets the stage for crunch.

6-Sixth Step: Add butter to topping
Drizzle in ⅓ cup melted butter. Stir with a fork until crumbly, like wet sand. Squeeze handfuls to form larger clumps for extra texture. Sprinkle evenly over the sweet potato base, covering completely.

7-Seventh Step: Bake the casserole
Preheat oven to 350°F. Place dish on a baking sheet to catch drips. Bake 25-30 minutes until edges bubble and topping turns golden brown. Rotate halfway for even browning. Broil 1-2 minutes at end for extra crisp if desired, watching closely.

8-Final Step: Rest and serve
Let cool 10-15 minutes on a wire rack. This sets the filling. Serve warm as a holiday casserole side. Cover leftovers promptly. Pairs great with turkey or ham for Thanksgiving.