This stuff is great!
We've been adding a little when we make soup, stew, mashed potatoes, pasta, bread, muffins and milkshakes. It even gets sprinkled on yogurt and granola at breakfast.
It takes 900 grams of fresh spinach to produced 100 grams of freeze-dried/powdered, so it's a great way to get a dose dark, leafy greens in winter.
It adds just a little toasty, vegetal flavour, something like matcha (roast green tea). It also adds a slight green tint, which can sometimes be a bit odd. Just remember the lesson of this classic:
As with all dried food, keep an eye on the sodium content. Small servings, about 1-2 teaspoons, will do.