France · Side
French Onion Soup
About this recipe
This recipe comes from a regional cooking tradition that draws on its own pantry, technique, and culinary history. The full editorial context for this cuisine is something we're still developing; the scaling and conversion tools above work the same regardless of origin.
As a side dish, French Onion Soup is designed to support a main course rather than command attention — built around vegetables, grains, or pulses with seasoning that lifts rather than dominates.
The scaler above resizes every ingredient to the number of servings you actually want; Cook Mode walks you through the recipe one step at a time with hands-free timers.
Recipe data is sourced from TheMealDB's open community database; ScaleRecipe handles the curation, the scaling math, the editorial commentary, and the conversion utilities woven into each page.
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Method
- Melt the butter with the oil in a large heavy-based pan. Add the onions and fry with the lid on for 10 mins until soft. Sprinkle in the sugar and cook for 20 mins more, stirring frequently, until caramelised. The onions should be really golden, full of flavour and soft when pinched between your fingers. Take care towards the end to ensure that they don’t burn.
- Add the garlic for the final few mins of the onions’ cooking time, then sprinkle in the flour and stir well. Increase the heat and keep stirring as you gradually add the wine, followed by the hot stock. Cover and simmer for 15-20 mins.
- To serve, turn on the grill, and toast the bread. Ladle the soup into heatproof bowls. Put a slice or two of toast on top of the bowls of soup, and pile on the cheese. Grill until melted. Alternatively, you can complete the toasts under the grill, then serve them on top.
Cooking notes
Scaling works best when you weigh ingredients rather than measure by volume — small differences in packing can compound at higher multipliers.
For volume-to-weight conversions of any ingredient — flour, sugar, butter, salts — use the ingredient converter. To translate the recipe's oven temperature between °C, °F and gas mark, see the temperature converter.
When you scale this recipe up or down, remember that cooking time does not scale linearly. A doubled cake takes longer, but not twice as long; a doubled soup takes roughly twice as long. The cooking-time guide gives sensible starting estimates by dish geometry.
Scaling notes
Scaling French Onion Soup
French Onion Soup is written for around four servings as it stands on this page — scaling it up for a party or down for a meal-for-one is the small math problem most home cooks face every week. Here's how this particular dish responds to scaling, what changes linearly, and what doesn't.
Side dishes scale more predictably than most categories. French Onion Soup cooks in roughly the same time at 1× and 2× because sheet-pan or sauté geometry doesn't change with batch size — only the depth of the layer does. Adjust seasoning by 1.5× when doubling, and watch the pan capacity: crowding a roasting tray means steaming, not browning.
Because this recipe is built around flour and sugar, weighing in grams (rather than measuring cups) is what separates a consistent bake from a one-time win. A cup of all-purpose flour can weigh 113 g or 150 g depending on how you scoop — that's a 30 % swing that ruins texture.
Butter is one of the easier ingredients to scale because it's sold in standardised sticks: 1 US stick = 8 tablespoons = ½ cup = 113 g. Any fractional scaling lines up neatly on a kitchen scale, and grocery-store butter packaging is already pre-marked in tablespoon increments along the wrapper.
Skip the math entirely — ScaleRecipe's scaler rewrites every ingredient line above with proper culinary fractions and smart unit promotion the moment you change the serving count. Open the scaler →
Beyond the recipe
Substitutions & make-ahead — French Onion Soup
Two things home cooks ask about most when they're outside the recipe's exact assumptions: what swaps work for which ingredients, and how the dish behaves when you make it ahead. Both depend on what French Onion Soup is doing structurally — here's the practical version.
Substitution ideas
Butter
For sautéing or browning, equal-weight olive oil or a neutral oil works directly. For baking, equal-weight coconut oil (melted, then chilled to the same softness the recipe expects) gives a buttery richness; a quality vegan butter brick is the structural match for cookies and pastries where firmness matters.
All-purpose flour
For gluten-free, a 1-to-1 gluten-free baking blend (one that contains xanthan gum) is the most reliable swap. For texture variations: bread flour gives chewier results; cake flour gives more tender. Avoid almond or oat flour as a 1:1 swap — they don't form gluten and most recipes structurally depend on it.
Cooking wine
Broth + 1 tbsp white wine vinegar or lemon juice per cup reproduces the acidic backbone. White grape juice for white-wine recipes; pomegranate or red grape juice for red. Non-alcoholic wines work directly but flavour varies wildly between brands — taste before committing.
For weight-based swaps and arbitrary quantities, the ingredient density converter and the cup-to-grams chart cover most pantry staples.
Make-ahead and storage
Side dishes vary widely in their make-ahead tolerance. French Onion Soup keeps well refrigerated if it's a roast, grain, or pulse dish — though roasted vegetables especially benefit from a hot-oven reheat (425 °F / 220 °C) to recapture some of their browned crispness. Microwaving makes them mushy. Mashed potatoes and creamed grains need a splash of milk or broth on reheating. Vinaigrette-dressed salads dress at serving time; mayonnaise-based salads benefit from overnight rest.
Recipe video
French Onion Soup
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Cooking aids
Tools to use while you cook this.
Each opens in a new tab so the timer keeps running. The math is auditable on the guide page below each converter, with worked examples and where the numbers come from.
Volume
Tablespoons, teaspoons, cups, ml, fluid ounces — every culinary volume unit, with US/metric/imperial cups handled distinctly.
OpenWeight
Grams, ounces, pounds, kilograms — exact for any ingredient, plus the volume-to-weight conversions for ~40 pantry staples.
OpenTemperature
Fahrenheit, Celsius, gas mark — translate any oven temperature, with notes on conventional vs convection.
OpenCooking time
The cube-root rule for scaling up, the differences between meat / cake / soup geometry, and sensible starting estimates.
OpenPan size
9-inch round vs 8-inch square vs 13×9. The math is surface area, not diameter — and the converter shows you both.
OpenLength
Inches and centimetres — for when a recipe says “cut into 1-inch pieces” and your ruler is metric.
OpenIngredient density
A cup of flour weighs 120 g; a cup of honey weighs 340. The full table of ~40 staples, with sources.
OpenOpen in main scaler
Edit the recipe text, scale by serving count, and copy the result. Same parser as the in-page scaler, more room to work.
OpenFrom the journal
Original essays on the small details.
The why behind the technique — original writing on the ingredient and equipment choices that separate a good cook from a frustrated one.
Reading a recipe like a chef
The 30-or-so recipe terms that show up most often, decoded
Read essayMay 4, 2026
Cooking for one — scaling principles
The math, the practical realities, and the recipes designed for one from the start
Read essayMay 4, 2026
How long do leftovers actually last?
Beyond the USDA's 3–4 days: the variables that actually determine the safe window
Read essayMay 4, 2026
Go deeper
Where this recipe sits in the wider tradition.
Each guide below is a real essay on the cuisine or the category — pillars, staples, techniques worth learning — paired with a curated grid of recipes filed under it.
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