Let me just tell you right now, this is delicious. Agrodolce sauce is good with many things although I think traditionally it is served with meat or fish. It is usually composed of thinly sliced and somewhat caramelized onion or shallots in a balsamic vinegar-sugar mixture. It is the sweet-and-sour sauce of Italy. Well, I'm a fan of green beans right now, especially the beautiful ones we are currently getting in the market up from Florida, so I decided that the sweet-sour-oniony treatment is just what they needed, plus a crispy, salty topping of pistachios to really highlight all that tangy sweetness. These went really well with a couscous and flank steak dinner we had last night, for which the recipes will be forthcoming.
First, I trimmed the ends off about a pound of attractive green beans, washed them well and set aside. I sliced up two very small onions--first in half and then crosswise to form thin half moon segments. You can use shallots or red onion if you prefer the flavor--I just didn't have any on hand. I melted together 2 tablespoons butter and 1 tablespoon olive oil over medium heat, added the onions and allowed them to cook for about 10 minutes until golden and lightly browned in parts. At that point, I added 4 tablespoons balsamic vinegar, 1 teaspoon brown sugar and 2 teaspoons raw sugar. Use whatever type of sugar you like, just not too much. You could probably try making this with honey also. Stir the vinegar, sugar and onions all together to form a syrupy sauce and try it to see if it needs any tweaking. I decided mine was too sweet so I added some white balsamic vinegar to temper it (the dark kind is naturally sweeter). Add a few cranks of salt and pepper, then set aside the sauce. Wipe out the pan, turn the heat up to medium-high and toast 1/4 cup of chopped, salted pistachios until crispy, then take them out and set aside. Add about 1 cup of water to your pan (I just kept using the same pan because I hate washing too many at the end) and get it boiling over high heat, then dump in your green beans to steam-saute. Let them get bright green and crisp-tender (about 4 minutes) then drain them. Toss the green beans in a serving dish with the agrodolce sauce and scatter the toasted pistachios over the top to serve.