These are very easy to do and the roasting takes all of the heavy onion taste out of them. As a matter of fact they have to be deglazed with a little white wine to counteract the sweetness by the time they are cooked. A delicious accompanient to anything: fish or meat.
Here is how you make them:
you will need.
2 to 3 boiling onions per person
a little olive oil
1 roma tomato
1 bay leaf
a sprig of thyme
2 cloves of garlic unpeeled
a little white wine
salt and pepper
Choose and approptialely sized fryng pan and put it on to preheat. Add a little olice oil to cover the bottom of the pan. When it is nice and hot add the onions that you have already peeled of course. Prick them a little with a fork before putting them in the fat. Let them simmer there until the start to get a little color then put them in the oven with the garlic cloves just like you would a roast. The oven should be of medium heat. When they are half cooked add the thyme, they bay leaf and the white wine with maybe just a dash of white wine vinegar to counter the sugar in the onion.
Let them finish roasting and when they are cooked the wine will be gone. Add the tomatos that you have chopped up and maybe a little cilantro or parsley and serve.
I add a whole jalapeno too but that is a question of taste. I like peppers.