French Onion Soup Tart [Gluten-Free]

This Gluten Free French Onion Soup Tart was inspired by a soup, but it serves up as an elegant tart. A bit of work, but impressive results!

Note: This recipe was first posted on my original blog, Celebration Generation, on June 25, 2020. It was transferred over to this blog - existing comments and all - on 9/20/2021

I developed this recipe for my first gluten-free cookbook, "Beyond Flour: A Fresh Approach to Gluten-Free Cooking and Baking".

Gluten-Free French Onion Soup Tart

I wanted to do a caramelized onion tart in general, but soon decided that I'd base all the flavours around French onion soup.

I liked the idea of including a custard base, as one would normally do for *dessert* tarts ... but a savoury custard, picking up more of the flavours of French Onion soup.

Everything came together so well!

Don't be intimidated by the long ingredient list - it's a little bit of work, but it's not especially difficult work.

This Gluten-Free Caramelized Onion Soup Tart is worth the effort - it makes an impressive offering for any brunch,dinner, or get together.

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Gluten Free French Onion Soup Tart

This Gluten Free French Onion Soup Tart may have been inspired by a soup, but it serves up as an elegant tart. A little bit of work produces impressive results!

Prep Time25 minutes mins

Cook Time1 hour hr

Chilling time1 hour hr

Total Time2 hours hrs 25 minutes mins

Course: Appetizer, Main Course

Cuisine: French, Gluten-free

Servings: 6

Calories: 693kcal

Author: admin

Equipment

• 10 inch Tart Pan

Ingredients

Crust:

• 1 cup Shredded Gruyere cheese
• ¾ cup Light buckwheat flour
• ½ cup White rice flour
• ¼ cup Sweet rice flour
• 1 tablespoon Tapioca Starch/Flour
• ¼ cup Corn starch
• 1 teaspoon Xanthan gum
• ½ teaspoon Salt
• ½ teaspoon Baking powder
• 1 Large egg
• ½ cup Lard
• ¼ cup Cold water

Caramelized Onions

• ½ cup Butter
• 3 lbs Sweet onions peeled and sliced
• ½ cup Dry white wine
• ½ teaspoon Salt
• 2 teaspoon Granulated sugar
• ½ cup Beef stock
• 1 teaspoon Chopped fresh thyme
• Salt and pepper

Custard Filling

• 2 tablespoon Butter
• 2 Garlic cloves pressed or minced
• ¼ cup Dry white wine
• ½ cup Beef broth
• 5 Large egg yolks
• 1 tablespoon Corn starch
• ¾ cup Milk
• 1 cup Shredded Gruyere cheese
• Salt and pepper

Instructions

Crust:

• Measure cheese, flours, starches, xanthan gum, salt, and baking powder into the bowl of your food processor, blitz to combine.
• Add egg and lard to the bowl, blitz a few times until mixture resembles gravel.
• Stream in cold water as you run the food processor, just long enough to bring it together as a dough.
• Remove dough from processor, knead lightly to bring it together as a ball. Wrap in plastic film, chill for 1 hour.
• Preheat oven to 350 F (180 C).
• Generously dust work surface with corn starch, Roll chilled dough out to a rough circle that's slightly bigger than 12" in diameter.
• Carefully transfer rolled dough to tart pan, smoothing the bottom and pressing the dough into the sides of the pan. Trim any excess dough that extends past the top of the pan, prick the flat (bottom) surface of the crust a few times with a fork.
• Bake for 25-30 minutes or until golden brown. While tart is baking, prepare your caramelized onions.

Caramelized Onions:

• In a large pot over medium-high heat, cook onions in butter until they start to soften.
• Add wine and salt, continue cooking - stirring often - until nicely brown.
• Add sugar and beef stock to pan, stir well, and continue cooking until onions are nicely caramelized.
• Remove from heat, stir in fresh thyme, season with salt and pepper to taste.

Custard Filling

• In a small saucepan, melt butter over medium heat. Add garlic, white wine, and beef broth, once again whisking until smooth. Gently bring mixture up to a simmer.
• While wine mixture is heating up, whisk egg yolks and corn starch together in a small bowl or measuring glass. once smooth, whisk in milk - a little at a time - until smooth and well incorporated.
• Once the wine mix has come to a simmer, add milk mixture, quickly whisking to fully blend the two. Bring up to a simmer again, whisking constantly. As it heats up, add the Gruyere cheese, stirring to melt and combine.
• Once custard has thickened to your liking, remove from heat, season with salt and pepper to taste

For serving hot:

• Spread hot custard in warm crust, top with hot caramelized onions, serve immediately.

For a cold tart:

• Allow everything to cool to room temperature before spreading custard in crust and topping with onions. Chill until serving.

Nutrition

Calories: 693kcal | Carbohydrates: 57g | Protein: 23g | Fat: 40g | Saturated Fat: 23g | Cholesterol: 292mg | Sodium: 927mg | Potassium: 544mg | Fiber: 5g | Sugar: 15g | Vitamin A: 1464IU | Vitamin C: 12mg | Calcium: 592mg | Iron: 2mg

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