Doubling a recipe.
What to watch for.

What to double exactly

For most recipes, multiply everything by two:

• —All main ingredients: flour, sugar, butter, eggs, dairy, meat, vegetables.
• —Flavourings like vanilla extract, spices, zest — double these too, though you may want to taste and adjust.
• —Liquids: water, stock, milk, wine — straight double.

Leavening agents: don't always double

Baking powder, baking soda, and yeast are the main exceptions. When doubling a recipe, start by increasing leavening by 1.75× rather than 2×. Over-leavened baked goods rise too aggressively, then collapse or develop a chemical aftertaste. A cake with too much baking powder will dome and crack; bread with too much yeast may over-proof.

As a rule: if the original recipe calls for 2 tsp baking powder, use 3½ tsp (not 4 tsp) in the double batch. Taste and adjust in future bakes if needed.

Salt: double, but taste

Salt technically scales linearly, but doubling a savoury recipe often brings out more intensity than expected — especially in slow-cooked dishes where liquid reduces. For soups, stews, and braises, double the salt but hold back 20% and season to taste at the end.

Pan size and bake time

Doubling a recipe doesn't always mean doubling the pan. A doubled cake batter fills two pans of the original size — not one pan twice as big. If you must use a larger pan, be aware that the batter will be shallower and bake faster, or deeper and bake slower.

For cookies and sheet-pan items, baking time stays roughly the same — you're just baking more batches. For loaves and cakes, if the pan is the same size, expect 10–20% more bake time for the center to set. Start checking early and use a probe thermometer or toothpick.

Awkward fractions when doubling

Some amounts become unwieldy when doubled: ¾ tsp becomes 1½ tsp (easy), but ⅔ cup becomes 1⅓ cups. The fractions the tool outputs are always the simplest kitchen-fraction equivalents, so you'll see "1⅓ cups" rather than "0.667 cups × 2 = 1.333 cups."

Cooking time for soups and stews

Doubling a soup or stew takes longer to come to a boil (more thermal mass), but the simmering time stays roughly the same. What changes is the time spent browning meat in batches — don't crowd the pan, or you'll steam instead of sear. Budget extra time for the prep and browning stages.

Gelatin, eggs, and thickeners

Gelatin doubles cleanly for most applications. Eggs are trickier — they come in whole units, and a recipe calling for 3 eggs that you double to 6 is fine. But a recipe calling for 1 egg that you triple to 3 is also fine. Where it gets awkward is halved or irregular amounts: "1.5 eggs" is typically 1 whole egg + 1 yolk, or 1 whole egg + 1 tablespoon beaten egg.

Equipment limits when doubling

Doubling a recipe doesn't just double the ingredient list — it doubles the volume of everything you're mixing, cooking, or baking. Before doubling, check whether your stand mixer bowl (typically 5–7 quarts) can handle double the dough without overflowing. Check whether your largest pot can hold double the soup. Check whether you have two pans of the right size, or enough oven rack space to bake two trays at once. Running out of bowl or pan capacity mid-recipe is disruptive; a quick equipment check before you start prevents it.

Strong flavours: double cautiously

Intensely flavoured ingredients — chili flakes, star anise, cloves, fish sauce, strong blue cheese — can overwhelm a doubled dish if scaled straight to 2×. The reason: extraction efficiency increases in larger volumes (more surface area contact time with the liquid), so the flavour compounds infuse more aggressively. Start with 1.75× for very strong spices and aromatics in a doubled batch, taste mid-cook, and adjust from there. Salt, vanilla extract, and mild herbs scale well at exactly 2×.