Is there anything that doesn't grow in California (besides sour cherries)? Even the fruits associated more with tropical Mexico or Hawai'i are able to grow here. Papaya trees are suddenly everywhere, looking like palm trees with jagged leaves and clusters of huge fruits at the crest of the trunk. While you can sometimes find ripe papayas at the farmers' markets, currently there are a few vendors selling unripe, green papayas.
Where a ripe papaya is mottled yellow or red, soft to the touch like a ripe peach, and filled with moist, edible, black seeds (they make wonderful salad dressing), unripe papayas are defiantly dark green, hard and full of bitter, hard, inedible white pips.
So why buy a green papaya, then?
For som tum, one of the glories of Thai street food. Som tum is shredded green papaya pounded in a mortar with sugar, fish sauce, garlic, chilies, vegetables, and either salted raw blue crab or a combination of dried shrimp and peanuts. The papaya acts as a vegetable rather than a fruit; while it has some hints of the coming sweetness, it is mostly an herbaceous, grassy flavor.
Look for firm specimens with little bruising and a fresh-looking cut. There should be no soft spots. They only cost a couple of dollars; buy one and experiment.
As for the salad, it's an easy recipe:
Som Tum (Thai Green Papaya Salad)
1 green papaya, about 1 lb.
3 large cloves garlic
1/3 c. palm sugar (substitute brown sugar)
3 Chinese long beans or 12 green beans, cut into 1-inch lengths
10 cherry tomatoes, halved
3 Tbsp. fish sauce
1 or 2 Thai chiles (small chiles; if you really love heat, go as far as 4 or 5), sliced
1/4 c. roasted, unsalted peanuts
2 Tbsp. dried shrimp without the shells
Raw cabbage, sliced into wedges
1. Peel the papaya, split it in half, and carefully cut out the hard white section and seeds.
2. Shred the papaya (having a food processor with a shredding disc is a real help here).
3. In a large, sturdy bowl, crush the garlic with the sugar using wooden implements (a heavy pestle or a couple of wooden spoons with thick handles).
4. Add the green beans and tomatoes and crush until the tomatoes give up their juice.
5. Add the papaya, fish sauce, chiles, peanuts and dried shrimp.
6. Pound and mix until the papaya bruises and the peanuts crack.
7. Serve with sticky rice and sliced raw cabbage.