Sweet Potato Gratin with Sage

Rich and flavourful, this sweet potato gratin with sage is a showstopper and a delicious twist on the traditional potato au gratin. 

I’m quite certain my US friends have their ingredients bought, their knives sharpened, and the ovens heating up in anticipation of their big Thanksgiving day feast. So apologies for posting this delicious sweet potato gratin a little too late if you already have your menu set. However, this is not a dish you serve only on special occasions. This is a lovely sweet potato gratin recipe that covers a range of occasions. Simple enough for a week-night meal, yet luxurious and decadent to be the star of your next celebratory feast.

More impressive, this gratin has only 6 everyday ingredients and couldn’t be simpler to make. You slice the sweet potatoes thinly (a mandolin is highly recommended), brush the dish and the top of the sweet potatoes with garlicky butter, add a little cream, and sprinkle the tops with fresh sage and parmesan cheese. This all gets roasted in the oven until the sweet potato flesh becomes tender and the tops get crispy and caramelized. Creamy, kinda sweet and salty, these sweet potatoes will make you want to leave behind the turkey and all the other sides.

MAKE-AHEAD SWEET POTATO GRATIN

This dish is happy to sit around for a while and be served at room temperature. To make well in advance, roast the sweet potatoes without the cream and parmesan cheese, covered with foil for 45 minutes. Once cooled, refrigerate up to two days. When ready to serve, add the cream and cheese and bake in a preheated oven, uncovered, for 20-25 minutes. Easy peasy.

Leftovers reheat beautifully. Top with a fried egg for breakfast (or dinner) or make a delicious frittata. Yum.

A FEW NOTES ON THE INGREDIENTS

This sweet potato gratin with sage recipe is slightly adapted from Ottolenghi Simple. Amazingly, and perhaps for the first time ever, I added, instead of omitted, a few ingredients to one of his recipes. Butter and parmesan. The butter to add a little sheen and help with the browning. The parmesan, well, because everyone loves a little cheese. Naturally, both of those ingredients are optional. And if you need this dish to be vegan, replace the cream with hemp milk which is really creamy and has more fat than almond milk.

I don’t use a lot of cream for this dish, and I don’t think you should either. Unlike a white potato gratin that dries out without copious amounts of cream, sweet potatoes will soften and tenderize with little, if any, added cream.

Make sure you buy sweet potatoes that have orange flesh, as opposed to the lighter white coloured flesh. In addition, try and pick potatoes that are similar in size so they fit your casserole dish evenly. If you prefer, feel free to replace the sage with rosemary or thyme.

This sweet potato gratin with sage is good, satisfying soul food with a wow-factor. If you’d like to leave the sweet potato casserole with marshmallows behind this year, do give this gratin a try. I’m pretty sure everyone will love it.

OTHER HOLIDAY SIDE DISHES YOU MAY ENJOY

• Brussels Sprouts with Agrodolce Sauce
• Delicata Squash with Pesto, Hazelnuts, and Sage
• Agrodolce Delicata Squash

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Sweet Potato Gratin

Author: Sandra Valvassori

Ingredients  

1x2x3x

• 6 medium sweet potatoes about 4 pounds total
• 2 Tablespoons butter
• 3 garlic cloves crushed
• 6 Tablespoons sage roughly chopped, plus extra to garnish (you can use chopped rosemary if you like)
• 2 teaspoons coarse sea salt
• ½ tsp freshly ground black pepper
• 3/4 cup heavy whipping cream
• 1/2 cup Parmesan cheese finely grated

Instructions 

• Preheat oven to 400º
• Scrub potatoes clean and trim the ends. Without peeling, cut into thin, 1/4-inch slices.*
• In a small sauce pan melt the butter over medium-low heat. Add the garlic cloves and sage and cook for about 1 minute - do not let the garlic burn.
• Lightly brush a 9"x13" casserole with the melted butter mixture, reserving some to brush the sweet potatoes.
• In a large bowl, toss the sweet potatoes with the salt and pepper. Stack the sweet potato slices in the casserole. Make tidy rows so you can see the edges of the skin.
• Brush the top of the sweet potatoes with the remaining butter mixture and tuck the garlic cloves around the potatoes. Cover the dish with foil, place in the oven and roast for 45 minutes.
• Remove from the oven, uncover, and pour the cream evenly over all potatoes. Give the dish a little shake to spread the cream around. Sprinkle with parmesan cheese all around the top.
• Roast, uncovered, for an additional 25 minutes or until the tops are slightly crisp and browned and the flesh is very soft and tender.
• Pull from oven and garnish with reserved sage. Serve immediately in casserole.

Notes

*A mandolin works well here to get thin, even slices. Or you can use a food processor if it has a thin slicing blade. If you don't have either, use a sharp knife and slice the sweet potatoes a little thicker to make your life easier. In this case, add about 15 minutes to the total cooking time.

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