Slow-Cooked Onions With Thyme And Parmesan

This easy Slow-Cooked Onions with Thyme and Parmesan is rich, creamy, and packed with flavor. The onions become beautifully tender, absorbing the thyme-infused cream sauce for a comforting side dish. With just a few simple ingredients, you can create a restaurant-worthy dish that pairs perfectly with roast meats or hearty mains. Sprinkle with Parmesan for the perfect finishing touch!

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Recipe Ingredients

10 small onions
250ml / 1 cup thin (pouring) cream
100ml / ⅓ cup + 1 tbsp good-quality vegetable stock
5 thyme sprigs, plus extra for garnish
3 garlic cloves, crushed
30g / 1 oz butter, chopped
50g / ½ cup finely grated Parmesan cheese

How To Make Slow-Cooked Onions With Thyme And Parmesan

Prepare the onions: Peel the onions and use a sharp knife to score a cross on the top of each one.
Assemble in the slow cooker: Place the onions in a slow cooker with the scored side facing up. Pour in the cream and stock, then scatter over the thyme sprigs, garlic, and butter. Season with salt and pepper.
Cook low and slow: Cover and cook on low for 5 hours, stirring occasionally, until the onions are tender.
Reduce the sauce: Carefully strain the cream mixture into a saucepan and simmer over medium-high heat for 7–10 minutes until thickened.
Finish and serve: Pour the thickened sauce over the onions, sprinkle with Parmesan, and garnish with extra thyme if desired. Enjoy!

Recipe Tips

Use small onions: Smaller onions cook evenly and absorb the flavors better. If using larger onions, cut them in half for even cooking.
Score the tops deeply: Make sure to cut a deep cross into each onion. This helps the sauce seep inside, making it extra flavorful.
Stir occasionally: While slow cooking, gently stir the onions now and then to coat them evenly in the creamy sauce.
Reduce the sauce properly: Let the strained sauce simmer until thick and velvety. A thin sauce won’t coat the onions well.
Serve immediately: These onions taste best hot and fresh, with Parmesan melting on top. If reheating, warm them gently to avoid separating the sauce.

Recipe FAQs and Variations

Can I Use Heavy Cream Instead of Thin Cream?

Yes, but it will make the sauce much richer. You can thin it slightly with a little extra vegetable stock if needed

Can I make this ahead of time?

Yes! Cook the onions and store them with the sauce in the fridge for up to 2 days. Reheat gently on the stove or in the oven before serving.

Can I add other herbs?

Absolutely! Try rosemary or sage for a different flavor twist, or add a bay leaf while cooking for extra depth.

What can I serve this with?

These onions pair well with roasted meats, grilled chicken, or even a vegetarian main like creamy mashed potatoes or risotto.

Can I make it without a slow cooker?

Yes! Bake the onions in a covered dish at 150°C (300°F) for about 2.5–3 hours, stirring occasionally.

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