While summer-ripened strawberries are sweet, juicy wonders, their green predecessors plucked far before their peak of ripeness have a consistency closer to cucumbers with just a hint of berry to keep things interesting. They are a little tart, a little acidic, and wholly delicious, particularly when turned into pickles. Follow your favorite quick pickle recipe (this sweet-spicy refrigerator pickle recipe is a winner) but swap in green strawberries for the sweet peppers or onions.
As for what makes for the perfect unripe strawberry, it's a bit up to the eater. Culinary powerhouse the James Beard Foundation spoke to several superstar chefs who all had different ideas about what to look for. One "insisted that a completely green berry, with no hints of white, is perfectly unripe," another looks "for green outsides and pink insides," and a third "likes fruit with 'little kisses of red or light pink.'" In short, whatever state of unripeness your strawberries happen to be in, they should work perfectly for pickles.
As for what to do with those little green wonders, add them to a cheese or charcuterie plate, use a few in a salad to add a bright note, or pair them with a simple fish or chicken dish to add a little zing. You could also include them as a savory element in a sweet dessert, and they frequently take a starring role in sorbets. They are also an intriguing and surprising addition to a cocktail. Nearly anywhere you would use a pickled onion or a lemon twist as a garnish, you could use a pickled green strawberry.