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Marinated and Slow-Roasted Onions

Salads 'n' Sides

Marinated and Slow-Roasted Onions


If you thought onions and red wine were relegated to Beef Bourguignon, well, here’s saying that’s not so. Flavorful, and with a look worthy of star billing, these onions are easy glamor for your meal. They can be prepared in a baking dish for table service, or, as shown, can be removed for stand-alone display and consumption. They will look super standing guard over your main course. The recipe is easy to adjust for more or fewer onions; you can also roast in individual ramekins if your meal presentation so commands.


For the marinade:

1 cup water
1 cup red wine vinegar
2 Tbsp brown sugar
1 tsp fresh chopped rosemary
1/2 tsp salt*
1/4 tsp black pepper*
Pinch red pepper flakes*

For the onions

4 large white or yellow onions
4 Tbsp butter
1 tsp fresh chopped rosemary


Blend the marinade ingredients in a small bowl and pour it into a baking dish that will hold all 8 onion halves.
Remove the dry and broken outer skin of the onion, leaving the tougher first layer (to help maintain structure). Trim the top and bottom of each onion and cut each onion in half horizontally.
Place the onions, wide side down, in the marinade; cover and refrigerate overnight.

Preheat your oven to 400 degrees. Flip the onions over in the marinade; they will be lying on the smaller, flat portion.
Top each half with 1/2 Tbsp of the butter and a sprinkling of rosemary.
Roast, uncovered, for 1 hour, or until golden brown, basting once or twice during roasting.
Remove from heat, and spoon the reduced sauce over the onion halves, Sprinkle with more of the fresh, chopped rosemary.
Remove the tough outer layer before serving and eating.

*I found that the onions needed more salt; I suggest that you roast according to the recipe, but be prepared to provide extra salt – it helps cut the acidity of the vinegar.
*A neighbor suggested that paprika or cayenne would give a little bite, and might also obviate the need for more salt.

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  1. Cynthia February 2, 2021

    Thank you so much for sharing. Been missing your posts! Crazy about roasted onions and going to try this recipe, for sure!

  2. Laura Lehmberg Austin March 13, 2021

    Fantastic….I usually cover half an onion in foil, put butter on top and a really nice seasoning salt. Bake about thirty minutes. Delicious. Yours is better…Thanks. Onions are healthy food.


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