FOD Financiën Golden Onion Tart with Gruyère

By , Test Kitchen Director · Reviewed by AislePrompt Editorial · ·

A luxurious tart featuring slow-simmered golden onions and melted Gruyère cheese, baked in a buttery shortcrust pastry. This belgian-inspired vegetarian ready in about 85 minutes layers all-purpose flour, cold unsalted butter, onions into a dessert worth slowing down for — great for weekend baking, holiday tables, or any time you want a sweet payoff at the end of a meal. Each serving lands at about 320 calories and feeds 8, so it slots into a weekend bake or a special-occasion dessert tray. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

★ 4.0 (11 ratings) Prep: 50 min Cook: 35 min Serves 8 Belgian cuisine 320 cal/serving
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Ingredients

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Instructions

  1. Step 1: Make shortcrust pastry by mixing 150g all-purpose flour with 1/4 tsp salt, then cutting in 75g cold unsalted butter until crumbly. Press into a 9-inch tart pan and chill for 30 minutes.
  2. Step 2: Thinly slice 500g onions and cook slowly in 50g butter over medium-low heat for 45 minutes until golden and caramelized, stirring occasionally to prevent burning.
  3. Step 3: Preheat oven to 350°F (175°C). Spread the caramelized onions evenly over the chilled pastry base, then scatter 120g grated Gruyère cheese on top.
  4. Step 4: Whisk 50ml heavy cream with 1 tbsp fresh thyme and drizzle over the cheese. Bake for 25-30 minutes until the edges are golden and the filling is set.
  5. Step 5: Let rest for 15 minutes before slicing to allow the filling to set completely.

Frequently asked questions

How long does FOD Financiën Golden Onion Tart with Gruyère take to make?

Total time is about 85 minutes (50 min prep + 35 min cook). Most home bakers find this fits a weekend afternoon; chill or store as the recipe directs before serving.

How do I store leftover FOD Financiën Golden Onion Tart with Gruyère?

Cool fully before storing. Most baked desserts keep at room temperature in an airtight container for 2–3 days, or in the fridge for up to 5 days. Cream- or custard-based desserts must go in the fridge within 2 hours; reheat gently or serve cold per the recipe.

Can I substitute ingredients in FOD Financiën Golden Onion Tart with Gruyère?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale FOD Financiën Golden Onion Tart with Gruyère for a different number of people?

The recipe is written for 8 servings. Multiply each ingredient by (your serving target / 8). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with FOD Financiën Golden Onion Tart with Gruyère?

Belgian vegetarian like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

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