Every recipe assumes you'll use the whole can, the whole bunch, the whole block. Cooking for one means you almost never do. The result is a fridge full of half-used everything, quietly turning into the actual reason groceries feel like they're going to waste, more than any single expensive ingredient.
The short answer
Most half-used cans, jars and bags fall into one of three fixes: freeze it in a usable portion, it keeps for weeks; find its one reliable second use, so it's not sitting there waiting for a specific recipe that may never come; or accept it's a five-day item and plan a second meal around it on purpose, instead of hoping you remember.
Specific fixes for the usual suspects
- Half a can of coconut milk: freezes fine in an ice cube tray, then bag the cubes. Two cubes is enough to finish a curry or soften a spicy sauce later.
- Half a can of tomato paste: spoon tablespoon-sized dollops onto parchment, freeze, then bag them. Drop one straight into a pan, no thawing needed.
- Half an onion: wrap tightly and it's fine for 4-5 days. Past that, dice and freeze what's left, texture suffers slightly but it disappears fine into a cooked dish.
- Half a bunch of herbs: chop and freeze in oil in an ice cube tray. This works far better than trying to keep fresh herbs alive in the fridge for a single person's pace.
- Half a block of tofu: keeps 3-4 days submerged in fresh water, changed daily. Or press and freeze it, the texture actually gets chewier, which some stir-fries benefit from.
- Half a bag of shredded cheese: freezes better than most people expect. It won't shred cleanly again, but it melts fine into anything cooked.
- Leftover wine, an inch in the bottle: freeze it in an ice cube tray specifically for deglazing pans later. This is what restaurant kitchens do, not a workaround.
The habit that actually solves this, not the trick
The freezing tricks above help, but the real fix is buying with the second use already decided. If a recipe needs half a can of something, know before you open it what the other half is for, tomorrow's lunch, not "I'll figure it out." An ingredient with no assigned second job is the one that quietly goes bad.
What genuinely isn't worth saving
Not everything is worth the freezer space. A small splash of milk, the last two tablespoons of a sauce, half a soft avocado gone brown, these cost more in mental overhead ("I should really use that") than they save in grocery money. It's fine to let the truly small stuff go.
Recipes that plan the second use for you
Every recipe in the cookbook is built around ingredients that reuse each other, so “half a can left over” isn't a problem you have to solve alone.
See the cookbook and bundles →Quick questions
How do you store half a can of coconut milk?
Freeze it in an ice cube tray, then transfer the cubes to a bag. It keeps for months and thaws in minutes for the next curry or sauce.
What's the biggest cause of food waste when cooking for one?
Half-used ingredients bought for a single recipe with no plan for the rest, not the price of groceries themselves.
What do you do with half a bunch of fresh herbs?
Chop and freeze them in oil in an ice cube tray, which works far better than trying to keep fresh herbs alive in the fridge for a single person's pace.
What's not worth saving when cooking for one?
Truly small amounts, like a splash of milk or the last two tablespoons of a sauce, cost more in mental overhead than they save in grocery money, so it's fine to let those go.