Found on a cooking show, take individual leek and holding with metal tongs and oven mit, hand roast the entire piece until black as coal. Let cool and scrape off charred leaves. Inside will be cooked leek ready to add to food processor, soups, etc. Assumes you're starting with very sand free produce, but saves effort of cleaning and chopping only to later puree. Fun thing to try with elementary school aged kids. Can do out of doors on the grill.
Always cook extra....or, stocking the fridge as you go. Start by making bases for foods your family already eats (we like potatoes, rice, pasta and lots of lettuce).
Got potatoes you need to boil? Make twice as much, use1/2 for soup, the other 1/2 for potato salad
Want pasta? Always make extra and while water boils make up dressing to make pasta salad base. Even if you don't finish making the salad that go round, you'll be on your way.
How about rice? Make twice as much, use 1/2 for Ambrosia, 1/2 for fried rice. MIx them up right away or just put that portion in a jar for when you will use it. I use 1/2 gallon mason jars for these, your base will fill it about 1/2 full. I like the jar as I can shake it between servings and it takes less room than a bowl would.
Buying greens? Soak separated leaves in cold water, rinse, dry, wrap in dish towel and package in a lidded container for storage in fridge. This way they're ready to use, chilled and they won't spoil before you need them if you keep swapping towels as they get wet. We eat more leafy greens when they're ready to use.
Following this habit of stocking up, you will eat more meals at home and will have less food waste since you will be using these ingredients pretty much daily. You can certainly quadruple rather than double your bases, we are a smaller household and we like some variety in our dishes.
Cooking batches ahead like this keeps the heat out of your kitchen and gives you starting points when you change (or don't have) dinner plans. Cooked rice will freeze as will cooked and sauced pasta, but boiled potatoes change in texture upon freezing so it isn't recommended.