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Vegetable Crumble with Onion Gravy

Vegetable crumble cooked in a delicious vegan onion gravy topped with an oaty savoury crumb before being baked until golden and bubbling.

This recipe is the perfect way to use up any leftover root veggies that you have knocking around!

Root vegetable crumble with an oaty crumb in a vegan gravy.

Veggie Crumble

Cooking for two can be a challenge, there are always a load of leftover vegetables.

Whether I’m making Welsh cawl soup, vegetable toad in the hole or Cornish pasties there are always loads of veggies leftover.

This simple vegetable crumble is often how I use up leftover root vegetables that I have hanging around.

It is delicious and is cooked in the most incredible vegan onion gravy. Which makes the whole dish a vegan delight.

The crumble topping is wonderfully savoury and features both sunflower seeds and oats to add texture.

It is by no means a quick meal to make but it is extremely easy and requires no special skills or kit.

It is also equally at home as a side dish as it is as a hearty vegan main course.

Overhead root vegetable crumble with an oaty crumb with a vegan onion gravy.

Frequently Asked Questions

Can I use other vegetables?

Yes, absolutely! I typically make this with whatever off-cuts of vegetables I have leftover.

Any root vegetables work well, also things like broccoli and cauliflower work well.

Do I have to parboil the vegetables?

For me, the root vegetables need a bit of a helping hand because they are a bit too firm if you do not.

Ingredients like cauliflower and broccoli do not need parboiling.

Can I use leftover roasted vegetables?

Yes, cut them up and pop them into the pot and pour over the gravy. Leftovers of stuff like roast potatoes, glazed carrots and roasted parsnips are great additions.

If the vegetables are already roasted they do not need parboiling.

Can I make this in advance?

Yes, the gravy can be made 2-3 days in advance and stored in the fridge.

The crumble can be assembled and placed in the fridge for a day or so before baking. Although the crumble is at its very best when added just before cooking.

Vegan onion gravy poured over a root vegetable crumble featuring a title overlay.

Serving Suggestions

I like to eat this vegetable crumble as a simple main with another veggie side. In for a penny in for a pound!

I often serve it with something like my braised cavalo nero kale with peas.

But it is equally good with anything from some simply cooked asparagus or roasted tenderstem broccoli.

It is also an exceptionally good side dish, stick it alongside roast chicken or some roast beef and it is fantastic.

Don’t worry about the vegan gravy, it is superb and stacks up really well against any gravy!

Vegan onion gravy poured over a root vegetable crumble.

Equipment Used

I only name-check equipment brands if I think they make a material difference to a recipe. If you have any questions feel free to ask them in the comments section below the recipe.

  • Oven.
  • Stovetop.
  • 18cm or 7″ saucepan.
  • 20cm or 8″ saucepan.
  • Chopping board.
  • Kitchen knife.
  • Mixing bowls.
  • Stirring spoons.
  • Sieve or colander.
  • Fine mesh sieve.
  • Blender.
  • 2 x 500-600ml (2-2½ Cup) baking dishes.
Root vegetable crumble served with a vegan onion gravy.
Yield: 2-4 Servings

Vegetable Crumble Recipe

Prep Time: 10 minutes
Cook Time: 1 hour 40 minutes
Total Time: 1 hour 50 minutes

This vegan vegetable crumble is a delicious way to use up leftover root veggies, it is cooked in a fantastic mushroom onion gravy and tastes fantastic.


  • 75g (⅔ Cup) Carrots
  • 150g (¾-1 Cup) New Potatoes
  • 100g (½ Cup) Parsnip
  • 125g (¾ Cup) Celeriac
  • 125g (1 Cup) Swede

For the Crumble Topping:

  • 75g (½ Cup + 1 Tbsp) Plain Flour
  • 35g (⅓ cup) Rolled Oats
  • 35g (¼ Cup) Sunflower Seeds
  • ½ Tsp Coarse Sea Salt
  • 1 Tsp Fresh Thyme
  • 50g (3 Tbsp + 1 Tsp) Vegan Butter

For the Onion Gravy:

  • 300g (2 Cups) Onions
  • 35g (2 Tbsp) Vegan Butter
  • 2 Tbsp Tomato Puree
  • 600ml (2½ Cups) Vegetable Stock
  • 25g (¾ Cup) Dried Porcini Mushrooms
  • 1½ Tsp Marmite
  • 1 Tsp Black Treacle or Molasses


  1. Peel the onions for the onion gravy then cut them in half lengthways and slice them into 5mm (¼") half-moon shapes.
  2. Heat the oil for the gravy in a medium 18cm or 7-8" (not nonstick) and over a low-medium heat.
  3. Add the onions to the oil and cook for 45 minutes, stirring every 10 minutes or so, when the onions are cooked they should be nice and golden.
  4. Peel the parsnip, celeriac and swede and cut them into 1.5cm (½-¾") cubes.
  5. Cut the carrots into 1cm (½") thick rounds.
  6. Cut the potatoes into 1.5cm (½-¾") chunks.
  7. Bring a 20cm or 8" saucepan of generously salted water to the boil, then parboil the parsnip, celeriac, swede and carrots.
  8. Add the potatoes to the pan with the vegetables and parboil for another 10 minutes.
  9. Mix together all of the ingredients for the crumble in a bowl and set aside.
  10. 15 minutes before the onions are ready bring the vegetable stock to a boil, then reduce the heat to very low.
  11. Add the dried mushrooms to the stock and allow it to sit for 10 minutes.
  12. 2 minutes before the onions are ready add the tomato puree and cook for 2 minutes stirring regularly.
  13. Blitz the stock and dried mushroom mix in blender then strain it through a fine-mesh sieve into the onions.
  14. Stir in the marmite and molasses into the gravy and simmer for 3-4 minutes.
  15. Build the crumble by separating the parboiled veg between 2 500-600ml (2-2½ Cup) baking dishes, then add the cauliflower florets add 250ml (1 cup) of gravy to each dish, then top with the crumble.
  16. Place the crumbles in the oven and cook for 45 minutes at 160°C or 302°F.
  17. Reheat the remaining gravy and use to serve on the side with the crumble.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 873Total Fat: 46gSaturated Fat: 8gTrans Fat: 6gUnsaturated Fat: 36gCholesterol: 0mgSodium: 2723mgCarbohydrates: 104gFiber: 14gSugar: 21gProtein: 18g

Calorific details are provided by a third-party application and are to be used as indicative figures only.

Did you make this recipe?

If you made this recipe, I'd love to see what you did and what I can do better, share a picture with me on Instagram and tag me @krumplibrian and tell me how it went!

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