Preheat grill pan (or outdoor grill) to medium/ medium high heat.
With a very sharp knife, cut each head in half through the root section and then in thirds. If you find that you have a small radicchio, simply cut the whole radicchio in quarters.
Brush the sides of the radicchio with olive oil.
Place on grill and carefully turn the radicchio every minute or so until the leaves begin to wilt. Continue to brush the tops with olive oil. This process should take about 5 minutes.
Transfer the grilled radicchio to a serving plate and sprinkle with salt and pepper.
Drizzle with balsamic vinegar.
Be careful to leave as much as the stem intact when trimming the end -this will ensure the radicchio does not fall apart when grilling it.
Feel free to top the grilled radicchio with grated cheese or shavings of Parmigiano-Reggiano
How do you make radicchio less bitter? Immersing the whole head of radicchio in water (for a few minutes) can reduce a little of the overall bitterness of this vegetable. Roasting and grilling is another great alternative.
Please keep in mind that the nutritional information provided below is just a rough estimate and variations can occur depending on the specific ingredients used.