In recipes that call for tomato paste, you usually only need a small amount, maybe a tablespoon or so. This leaves you with a surplus of paste, and if you're not planning on using it for any other meals, salvage that paste by freezing it into spoonfuls.
This tip comes via Cadry's Kitchen. She explains how it works:
I made some room in the freezer. Then I lined a baking sheet with parchment paper. With a measuring spoon, I doled out tomato paste in tablespoon-sized dollops like red tomato-y cookies. I then popped the sheet into the freezer until the paste patties were solid.
Once they were completely frozen separately, I just moved the solid tomato paste patties into a glass container. I marked the outside of the glass with a black permanent marker, so that I'd know what was inside.
This way, next time you have a recipe that calls for tomato paste, you can simply toss in a patty. Check out the tip for yourself at the link below.
Quick Tip: Freeze Tomato Paste and Never Toss a Moldy Jar Again [Cadry's Kitchen]