How many servings does this recipe make?

This recipe makes 4 servings. You can adjust the portion size directly on this page.

What ingredients do I need for Caramelized Onion & Mustard Tart?

You need 10 ingredients. The key ingredients include: 50 g butter, 1 tablespoon olive oil, 4 large yellow onions, sliced, 1 garlic clove, crushed, and more.

Is Caramelized Onion & Mustard Tart suitable as baking & desserts?

Yes, Caramelized Onion & Mustard Tart falls under the Baking & Desserts category and is a great choice for this type of meal.

How do I store leftover Caramelized Onion & Mustard Tart?

Store in an airtight container at room temperature for up to 3–5 days. For longer storage, freeze for up to 3 months — no need to refrigerate or reheat.

Caramelized Onion & Mustard Tart Recipe

Name: Caramelized Onion & Mustard Tart
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Yield: 4 servings
Ingredients: 50 g butter; 1 tablespoon olive oil; 4 large yellow onions, sliced; 1 garlic clove, crushed; 2 eggs; 2 egg yolks; 50 g coarse grain mustard; 142 ml double cream (US, heavy cream); 2 tablespoons of fresh mint, chopped; 1 pie crust

Bake this irresistible Caramelized Onion & Mustard Tart at home. Made with butter, olive oil, yellow onions and garlic. Easy step-by-step instructions i…

This Caramelized Onion & Mustard Tart relies on simple, everyday ingredients such as butter, olive oil, large yellow onions, sliced and garlic clove, crushed. It comes together quickly and makes 4 servings, at about 474 kcal each. The step-by-step instructions below are written to be easy to follow, even on a busy day.

Whether you're rounding off a family dinner, bringing a treat to a gathering, or simply satisfying a sweet craving, this Caramelized Onion & Mustard Tart delivers. Serve it warm or at room temperature, and add a scoop of ice cream or a spoonful of whipped cream for an extra-special finish.

Updated Jun 30, 2026

Serves 4 Baking & Desserts

Tips for the best results

Read through all the steps once before you start and measure out your ingredients first — it makes everything go more smoothly.
Preheat the oven fully and bake on the middle rack for the most even results.
Check for doneness a few minutes early — a toothpick in the center should come out with just a few moist crumbs.
Let it cool before slicing so it sets properly and holds its shape.
Store leftovers in an airtight container in the fridge and enjoy within a few days.

Variations & substitutions

Use a neutral oil or a plant-based spread in place of butter for a dairy-free version.
Coconut cream is a reliable plant-based alternative to dairy cream.

No specific allergen information. Please check the ingredient list for possible allergens.

My Personal Notes

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Caramelized Onion & Mustard Tart

Tips for the best results

Variations & substitutions

My Personal Notes

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