Frozen peas add a pop of sweetness and colour to all sorts of dishes, but I particularly appreciate them in rich soups and stews. Their bright flavour offers a bit of vegetal respite from meaty and creamy flavours and — if you add them right at the end — they can help cool your soup down to a reasonable, less painful temperature.
Adding frozen peas at the very end of the soup-cooking process is good for the peas and for the soup as a whole. In spite of what most pea packaging says, frozen peas cook through in a couple of minutes (sometimes less, depending on how scorching your soup is). Put them in too early, and the peas end up mushy, losing the texture that makes them such a delight in the first place.
Also, by adding a scoop of frozen peas to soup that is too hot to heat, you cool the soup to a temperature that is still hot, but less likely to cause injury. Everyone wins, including your mouth (which has been burned before, I’m sure). Just cook your soup as you normally would and, once you’re ready to serve it, stir in the peas, let them cook for a minute or two, and serve your soup.