>every once in a while you'll run into a variety of produce that only really works for fresh & doesn't lend well to processing. This mostly happens w leafy greens (we don't make … lettuce sauce)

I wish I could buy frozen lettuce. Lettuce can be cooked (e.g. for lettuce soup), and cooked lettuce loses the crisp texture, so there's no drawback to freezing it first. The idea that lettuce is only a salad vegetable is an irrational tradition, like the idea that there are foods only suitable (or unsuitable) for breakfast. I'd eat more lettuce if it wasn't so expensive compared to frozen spinach.