Duchess Sweet Potatoes with Brown Butter Sage

I walked into Whole Foods Grocery Store to return gift items at the Amazon Customer Service Center and walked out with Louisiana sweet potatoes. The sweet potatoes were right inside the entrance to the store. Too tempting to walk by them without purchasing several. This root vegetable has lots of nutritional value. Plus, they are in season and inexpensive. So, there you go — three good reasons for why to purchase sweet potatoes. Today, I am making “Duchess Sweet Potatoes” which is a jazzed up concoction of mashed potatoes. I added browned butter with sage to give a upscale flavor. I even located my pastry piping bag and star tip to bake the potatoes little swirl shapes which is what makes “Duchess Sweet Potatoes” special. These creamy potatoes are just as good for when baked in a casserole dish as piped onto a platter for a fancy holiday dinner.

I am trying hard to find ways to use the fresh sage which a friend gave me. The fresh sage leaves lasted for several weeks by storing them in water on my kitchen counter. Now, in December the sage has dried out — but the leaves still retain their pungent flavor. Now it is time to use the sage. The brown butter sage adds “punch” to this dish.


A very simple way to cook these sweet potatoes is simply to boil and mash the potatoes. Then add warm milk, brown butter with sage, salt and pepper and bake the casserole. With this recipe, the sweet potatoes are smooth and mild — just like traditional mashed potatoes. An egg is added to Duchess Potatoes, which differentiates this dish from mashed sweet potatoes.

Here’s the casserole after baking. I added pecan pieces prior to baking in the oven and added fresh parsley from my garden for garnish.

Duchess Potatoes

Duchess Potatoes traditionally are mashed potatoes which are piped into little swirls and baked. This makes for an impressive side dish for a holiday dinner. For this effect, you need an open star piping 1 M tip and piping bag.

However, if cake decorating and piping is not in your skill set, then there are other ways to accomplish this effect. Place dollops of sweet potatoes on a parchment lined sheet pan, then press with fork to make an attractive design with the fork tines and skip the pipping step. Bake for about 20 minutes until the dollops are set. No one will know that you didn’t pipe these little sweet potato gems. Alternately, bake the sweet potatoes in a casserole dish.

Making the Recipe

The easiest way to make this recipe is to peel, boil, drain and mash the sweet potatoes. Gently boiling the potato chunks for 20 minutes gave time for the sweet potatoes to cook completely and become soft. Drain, then mash the sweet potatoes using a potato ricer.

If you are going to pipe the the sweet potatoes into swirls, then the sweet potatoes need to be completely mashed with no chunks. The potato ricer works great. I recommend investing in this inexpensive kitchen gadget. For piped potatoes, the mixture needs to be stiffer — add less milk — so the swirls will set.

Mix the egg, warmed milk, melted brown butter sage, salt and a pinch of black pepper into the sweet potatoes. For the casserole, add more milk, if needed, to make a creamy textured sweet potato mixture. Use less milk, if pipping, for a firmer mixture.

Brown Butter Sage

To add an aromatic dimension to this casserole dish, I added brown butter with sage. However, this is optional if your family does not care for the flavor of sage.

Making brown butter with sage is very simple. Just watch the stove to avoid burnt butter. To make brown butter, first cut the sage into small slivers. If using fresh sage, then roll them up and use a knife to slice across the rolls. For dried sage, just crumble the sage. Add butter and several sage slivers to a small heavy pot over low heat. And I emphasize, low heat. The butter will bubble and melt. The sage cooks. Stir frequently. When the butter turns to golden brown, immediately remove from stove. No need to separate the butter solids from the liquid as for clarified butter. Let the sage steep in the butter. Then decant off the bits of sage prior to adding to the sweet potatoes.

This smooth and creamy rendition of “Duchess Potatoes” is very tasty and the flavor is easy on the palate. Brown butter with sage adds an aromatic dimension. Whether or not go to the extra effort to make little sweet potato swirls, this is a very simple way to include a nutritional vegetable into meals. Enjoy!

Duchess Sweet Potatoes

  • Servings: 8 servings
  • Difficulty: easy
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  • 2 medium sweet potatoes (about 1-1/2 lb total)
  • 1 large egg
  • 1/2 cup milk, more if needed
  • 2 Tbsp butter
  • 1/2 tsp salt
  • dash black pepper
  • 1/2 cup chopped pecans, optional
  • fresh parsley, optional garnish

Optional Ingredients for Sage Butter:

  • 2 Tbsp butter
  • 6 fresh sage leaves or 2 Tbsp dried crush sage leaves

Method and Steps:

  1. Pre-heat oven to 350 degrees. If making sweet potato dollops, place a piece of parchment paper on a large baking sheet. Alternatively, oil a 2-quart casserole dish.
  2. Peel sweet potatoes and cut into large chunks.
  3. Place chunks in medium-size sauce pan with water to about 1″ in depth. Bring water to boil, then lower heat of burner. Simmer sweet potato chunks until tender, 20 minutes.
  4. Remove sweet potatoes from stove, drain. Transfer to large bowl. Use a potato ricer to mash sweet potatoes. (If pipping sweet potatoes, potatoes need to be completely mashed with no chunks remaining.) Set aside.
  5. Make sage brown butter. Roll sage leaves up into a tight roll. Use a small knife to slice into tiny slivers. Add butter to small heavy saucepan. Add sage slivers. Heat butter over low heat until butter melts. Stir and cook until butter turns golden brown. This may take about 5 minutes when cooked over low heat.  Watch carefully, as the butter can quickly burn. Immediately remove from stove when butter browns. Set aside and let steep. Prior to adding to sweet potatoes, decant off bits of sage.*
  6. Add egg to cooked and mashed sweet potatoes. Use a wire whip to combine.
  7. Heat milk in microwave for about 30 seconds.
  8. Add sage brown butter, warm milk, salt and a dash of black pepper to mashed sweet potatoes. Use wire whip to beat until mixture is creamy and smooth. For piping, mixture should be thick. However, if finishing in casserole dish, add several tablespoons additional warm milk, if needed, for a smoother mixture.
    1. Fill a piping bag fitted with a large open star (1M) tip with sweet potato mixture. Pipe swirled rounds onto parchment paper. Refill piping bag until all sweet potato mixture is used. Or, place dollops of sweet potatoes on parchment paper with a large spoon. Use the tines of a fork to mash the dollops and create an attractive design.
    2. Alternatively. place sweet potato mixture into oiled 2-quart casserole dish. Sprinkle chopped pecan pieces on top.
  9. Bake sweet potato swirls in 350 degree oven 20 minutes until they are set. (For casserole, bake for 30 minutes.)

*NOTE: Brown butter sage can be omitted. Instead, melt 2 Tbsp butter along with milk when warmed in microwave.

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