Ingredients

1.75kg / 3.5lb sweet potato (3 large or 6 smaller ones)

1/2 cup (115g) sour cream

1/2 cup (50g) parmesan, freshly grated

2 garlic cloves, finely minced

3/4 tsp salt

1/4 tsp black pepper

250g / 8oz salted butter, cut into 2cm (1″) cubes

15 sage leaves

3/4 cup panko breadcrumbs

1/2 cup (50g) parmesan, finely grated

1/4 tsp salt

1/4 tsp black pepper

150g / 5oz streaky bacon, cooked until golden then finely chopped

Instructions

Step 1: Preheat the oven to 180°C (350°F). Place the sweet potatoes on a foil-lined tray and bake for 1 hour 15 minutes (if small) to 1 hour 40 minutes (if large), until a knife can be easily inserted into the center.

Step 2: Allow the potatoes to cool until they can be handled, but remain piping hot inside. You can use a tea towel to handle them safely.

Step 3: Meanwhile, melt the butter in a large saucepan over medium heat. When it starts to foam, add the sage leaves. Cook for about 1 minute or until the leaves turn golden. Remove the leaves with a slotted spoon and drain on paper towels; they will crisp as they cool.

Step 4: Continue cooking the butter until the foaming stops and you see brown bits at the bottom of the pan; it should have a nutty aroma. Strain the browned butter through a paper towel-lined sieve, reserving about 180ml (3/4 cup).

Step 5: Prepare the topping by crumbling the crispy sage leaves into a bowl. Add 1/4 cup of the browned butter, panko breadcrumbs, parmesan, garlic, salt, and pepper. Mix well and set aside.

Step 6: Cut slits down the middle of the baked sweet potatoes and scoop the flesh into a bowl. Add 1/4 cup of the browned butter, sour cream, parmesan, salt, and pepper. Mash with a potato masher or electric beater until smooth. Avoid over-processing to prevent a gluey texture.

Step 7: In a 2-liter (2-quart) baking dish, spread half of the mashed sweet potato. Create swirls on the surface with a spoon to catch the butter pools, then drizzle with 1/4 cup of the browned butter. Carefully cover with the remaining mashed potato, trying not to disturb the butter.

Step 8: Sprinkle the prepared topping evenly over the surface. Bake for 25 minutes until the top is golden and the edges are bubbling.

Step 9: Remove the casserole from the oven, sprinkle the chopped bacon over the top, and bake for an additional 5 minutes. If you have any remaining browned butter, drizzle it on before serving for extra richness.

Tips & Variations

Use fresh sage for the best flavor and crisp texture in the topping. If unavailable, dried sage can be used sparingly but won’t crisp as well.

For a vegetarian version, omit the bacon and add toasted walnuts or pecans for added crunch.

To save time, cook the sweet potatoes in advance and refrigerate; reheat before assembling and baking.

Be careful not to over-mash or process the sweet potatoes to avoid a gluey texture.

FAQs

Can I use regular potatoes instead of sweet potatoes?

Yes, but note that the flavor and sweetness will differ. Regular potatoes will create a more neutral mash, and you may want to adjust seasoning and add a bit more sour cream or butter for richness.

How do I make the browned butter and sage topping ahead of time?

You can brown the butter and crisp the sage leaves up to a day ahead. Store the browned butter in the fridge and crisp sage in an airtight container at room temperature. Combine all topping ingredients just before assembling the casserole.