sweet potato au gratin with sautéed onion and a rosemary béarnaise sauce

The weather here in TN is unlike anything I’ve experienced before. One day it’s 75 degrees, then the next day it’s 42. I can’t plan any meals based on weather like we would during winter or summer right now as we seem to be in-between and everything is settling. So, I pick what is in season and what is low histamine… savory… easy. These are the goals I have every week and this meal basically makes itself.

You Will Need:

Sweet Potatoes (one medium / large per person)
White Onion (yellow or sweet if you tolerate)
Half & Half or Heavy Whipping Cream
No Sugar Added Vanilla Macadamia Nut Milk (or another milk if you tolerate)
Unsalted Butter (we love Kerrygold)
Sea Salt
Dried Rosemary
Fresh or Shredded Mozzarella
Spelt Flour
Any additional micro-greens topping or fresh herbs (optional)

Take your potatoes and slice them down into quarter inch pieces, layering them together so that if you’re using individual vessels like I am, each person will get the same amount of potatoes. If you’re cooking this in one large casserole dish, just cut your potatoes and set aside.

Dice your onion and sauté in a pot with melted butter. I used a tablespoon of butter per serving and half of the onion because we really like the flavor. Use as much onion as you’d like. If you’re serving more than two people, adjust the butter accordingly.

After that cooks down, and when the onions are softened, reduce the heat to medium / medium low and add two tablespoons of spelt flour. I used one tablespoon per serving. If you’re serving more than two people, adjust the flour accordingly.

Whisk the flour and butter together, making sure the heat remains on medium / medium low. Then add a tablespoon of your dried rosemary (one tablespoon per two servings – adjust accordingly). Stir that in while adding a quarter cup of half and half / whipping cream (a quarter per two servings – adjust accordingly).

Then add a half a cup of the macadamia nut milk (a half a cup per two servings – adjust accordingly). and continue to stir (you can also whisk if you find that easier). It’s okay if there’s still some small clumps of flour. Take two handfuls (one handful per serving) of the shredded mozzarella and add it to the pot to melt. If you got fresh mozzarella, I would use a similar chopped measurement.

Take your vessel(s) and layer a spread of the sauce on the bottom (think of this as lasagna).

Depending on the type of dish you choose, you can do a spiral or long layers of potato. I have these round dishes and wanted to do a spiral. I took care to make sure each person had similar sized potatoes… You may wish to do the same.

Then cover the potatoes with the sauce and spread just a bit (I will spread out on its own a bit once it heats in the oven).

Then again with potatoes.

And once more with sauce.

Put them in the oven on 350 for 30 minutes.

The tops will get very brown which I liked (it is not burnt, it’s just the color) however, if you don’t, leave the casserole(s) covered for at least half of the cooking time and then remove the foil so it becomes less dark.

When it came to plating I wanted to keep it simple, adding just some pea shoots. You can add parsley, more rosemary, spinach (though not low histamine so instead use kale), watercress, etc.

You can see all the soft creamy layers when cutting into the casserole.

I made two and saved one in the freezer – just make sure you cover the top with plastic wrap first and then with foil. When ready to eat, leave in the fridge a bit to defrost and then reheat in the oven – leaving the aluminum foil over the top if you don’t want any further browning.