low sugar onion gravy in a ceramic mug with wooden spoon and mashed potato — sugar swap recipe by Mel

With The SwapLess Sugar*

Low Sugar Onion Gravy — The Sunday Roast Swap

Name: Low Sugar Onion Gravy
Prep time: 5 min
Cook time: 35 min
Total time: 40 min
Yield: 8 servings
Cuisine: British
Ingredients: 2 large yellow onions thinly sliced; 2 tbsp butter or ghee; 2 cups beef bone broth unsweetened; 1 tsp Worcestershire sauce sugar-free; ¼ tsp xanthan gum; salt and black pepper to taste

I did not expect gravy to be a sugar problem. And then I started reading the labels on stock cubes and shop-bought gravy and found sugar listed as an ingredient in almost all of them. Why is there sugar in gravy? Nobody knows. But there it is.

This version builds its flavour the right way — slow-caramelised onions, proper bone broth, and a long, patient simmer. The colour comes from the onions. The depth comes from time. No flour, no added sugar, and genuinely better than anything from a packet.

It takes 35 minutes, which is the honest truth about why good gravy is good.

Prep5 min

Cook35 min

Serves8 (¼ cup)

Sugar1g*

Jump to Recipe ↓

Traditional brown gravy (6g sugar per ¼ cup)→Caramelised onion bone broth gravy (1g sugar)*

*Per USDA FoodData Central

⇄ The Swap Snapshot

Typical Version	The Sugar Swap Version	Sugar per ¼ cup*
Traditional Brown Gravy White flour roux, sugar-added beef stock — hiding in plain sight	Low Sugar Onion Gravy Caramelised onions, beef bone broth, xanthan gum	6g→1g

*Based on USDA FoodData Central values. The Sugar Swap is not medical or nutritional advice.

Ingredients

Makes about 2 cups · 8 servings (¼ cup each)

2 large yellow onions, thinly sliced
2 tbsp butter or ghee
2 cups beef bone broth (unsweetened)
1 tsp Worcestershire sauce (sugar-free)
¼ tsp ⇄ xanthan gum — replaces flour
to taste salt and black pepper

Instructions

1
Melt butter in a large skillet over medium-low heat. Add onions and a pinch of salt.
2
Cook for 25–30 minutes, stirring occasionally, until the onions are deep golden brown and properly caramelised. Don't rush this step.
⇄ Swap Note
The long, slow caramelisation is what gives this gravy its dark colour and depth — normally achieved with caramel colour or sugar in commercial gravies. This is better.
3
Pour in the beef bone broth and Worcestershire sauce. Bring to a simmer.
4
Whisk in the xanthan gum and simmer for 5 minutes until thickened to your liking.
5
Season with salt and pepper. Serve over mashed potato or roast beef.

⇄ The Swap Reason

Thickening Your Gravy Without White Flour

Traditional gravy is thickened with a flour roux, which adds carbohydrates and requires added fat to work. Xanthan gum achieves the same silky consistency without any carbs, and in much smaller quantities. Bone broth replaces commercial stock (which often contains added sugar and flavourings), adding collagen and genuine depth. See the Swap Guide for more on xanthan gum and when it works best.

Common Mistakes

⚠
Rushing the onions. Caramelisation takes 25 minutes minimum. If your onions aren't deep golden brown, the gravy won't have the right colour or depth.
⚠
Adding too much xanthan gum. A quarter teaspoon is enough for 2 cups of liquid. More than that and the texture becomes unpleasantly thick.

Storage

Store in a sealed container in the fridge for up to 4 days. Reheat gently on the hob with a splash of water if needed. Freezes well for up to 3 months.

Nutrition per serving (¼ cup)

40Calories

2gProtein

3gCarbs

2gFat

1gFiber

1gSugar*

*Per USDA FoodData Central · Typical version: 6g sugar per ¼ cup · The Sugar Swap is not medical or nutritional advice.

Frequently Asked Questions

Can I make this vegetarian?

Yes — swap the beef bone broth for a good quality vegetable broth. The flavour will be lighter but still excellent.

What can I serve this with?

Mashed potato, roast beef, roast chicken, cauliflower mash — it's a versatile base sauce. It's also excellent over a low-sugar lentil dish for a hearty plant-based meal.