Old-Fashioned Sweet Potato Casserole with Pecan Streusel

Some recipes never leave the family table, and this is one of them. This sweet potato casserole came from Grandma’s church cookbook — the one with the splattered pages and the handwriting in the margins — and it has shown up at every Thanksgiving and Christmas dinner since before I can remember.

The filling is silky and rich, mashed sweet potatoes with butter, a little brown sugar and warm spices. But the streusel is what people talk about on the drive home: a thick, crunchy blanket of pecans, brown sugar and butter that bakes up golden and crisp, like the top of a pecan pie met the best part of a crumble.

Best of all, it’s a make-ahead friend. Assemble it the day before, keep it in the fridge, and bake it while the turkey rests. One less thing to juggle on the big day — Grandma planned it that way.

Why This Recipe Works

• Real sweet potatoes, mashed smooth — no canned filling, no shortcuts. The texture is creamy all the way through.
• Streusel with a crunch that lasts — flour and cold butter rubbed in by hand, so it bakes up crisp instead of sinking in.
• Make-ahead friendly — the filling actually tastes better the next day, and the topping goes on right before baking.

Old-Fashioned Sweet Potato Casserole with Pecan Streusel

Silky mashed sweet potatoes with butter and warm spices, baked under a thick, crunchy pecan streusel. The church-cookbook classic — make it ahead for Thanksgiving.

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Prep Time 20 minutes mins

Cook Time 35 minutes mins

Total Time 55 minutes mins

Servings: 10

Course: Side Dish

Cuisine: American

Calories: 412

Ingredients Method Notes

Ingredients

  

For the filling

• 4 lbs sweet potatoes about 5–6 medium, peeled and cut into chunks
• 1/2 cup unsalted butter melted
• 1/2 cup brown sugar packed
• 1/3 cup milk whole milk is best
• 2 large eggs room temperature
• 1 1/2 tsp vanilla extract
• 1 tsp ground cinnamon
• 1/4 tsp ground nutmeg
• 3/4 tsp salt

For the pecan streusel

• 1 cup brown sugar packed
• 1/2 cup all-purpose flour
• 1/2 cup cold unsalted butter cut into small cubes
• 1 1/2 cups pecans roughly chopped
• Pinch of salt

Method

 

1. Heat the oven to 350°F (175°C). Grease a 9×13-inch baking dish with butter.
2. Put the sweet potato chunks in a large pot, cover with cold water, and add a pinch of salt. Bring to a boil, then simmer 15–20 minutes, until very tender when poked with a fork. Drain well and let the steam drift off for 2–3 minutes — this keeps the filling from going watery.
3. Mash the sweet potatoes until smooth (a hand masher leaves a little character; a mixer makes them silk). Stir in the melted butter, brown sugar, milk, eggs, vanilla, cinnamon, nutmeg and salt until everything is glossy and combined.
4. Spread the filling evenly in the prepared dish.
5. Make the streusel: in a bowl, rub the brown sugar, flour and cold butter together with your fingertips until it looks like coarse crumbs. Stir in the pecans and the pinch of salt.
6. Scatter the streusel thickly over the filling, edge to edge.
7. Bake 30–35 minutes, until the topping is deep golden and crisp and the filling is bubbling at the edges.
8. Rest 10 minutes before serving — it sets up and slices cleaner. Serve warm.

Notes

Make ahead: assemble the filling in the dish, cover and refrigerate up to 2 days. Keep the streusel separate in a bag in the fridge; scatter it on just before baking and add 5–10 minutes to the bake time.

Leftovers keep 4 days in the fridge and reheat beautifully at 325°F.

Nutrition is an estimate per serving.

Grandma’s Tips

1. Dry potatoes, rich casserole. Let the drained potatoes steam in the hot pot for a couple of minutes. Extra water is the enemy of a silky filling.
2. Cold butter in the streusel. Warm, melted butter makes a paste; cold butter rubbed in makes crumbs — and crumbs bake up crisp.
3. Taste before the eggs go in. Sweet potatoes vary. If yours are on the blander side, add another spoonful of brown sugar or a pinch more salt.
4. Chop the pecans rough. Big pieces toast better and give you that pecan-pie crunch in every bite.
5. Watch the last 5 minutes. Streusel goes from golden to dark fast. If it’s browning early, tent loosely with foil.

Frequently Asked Questions

Can I make sweet potato casserole ahead of time?

Yes — it’s one of the best make-ahead Thanksgiving sides. Fill the dish, cover and refrigerate up to 2 days. Add the streusel right before baking so it stays crisp.

Can I use canned sweet potatoes or yams?

You can. Use two 40-oz cans, drained very well, and cut the brown sugar in the filling to 1/3 cup since canned are packed sweeter. The texture will be a touch softer.

My streusel sank into the filling — what happened?

Usually the butter was too warm, or the topping went on a hot filling. Rub cold butter in, and let the filling cool a few minutes before scattering the streusel.

Can I freeze it?

Freeze the unbaked casserole (without streusel) up to 2 months. Thaw overnight in the fridge, add fresh streusel, and bake as directed.

What if someone can’t eat nuts?

Leave the pecans out and add 1/2 cup old-fashioned oats to the streusel instead — still crunchy, still delicious.