-Whisk together the following in a large bowl:
2 TBS balsamic vinegar
3 smashed garlic cloves
1 TSP fresh lemon juice
½ cup olive oil
½ tsp sea salt and some freshly ground black pepper
-Cut 1 head of radicchio into thin ribbons and put it on a baking sheet and toss with 2 more TBS olive oil.
-Broil 5 to 6 inches from heat, turning occasionally, until slightly wilted, 3 to 4 minutes.
-Add hot radicchio to balsamic marinade and gently toss to coat.
-Cover bowl (to keep heat in) and marinate, tossing once or twice, at least 1 hour.
-Transfer radicchio to a serving dish, pouring some of marinade over top.