You hardly need a recipe for this.
Cut the radicchio into wedges and bake them in a 350 degree
oven.
When they’re at the right degree of tenderness, sprinkle blue
cheese crumbs and balsamic vinegar on top, and put under broiler
until the cheese melts.
When I make this for myself for a main dish, I use half of a large head of
radicchio and put a layer of rice under the wedges. I like the
radicchip pretty al dente, so I only bake for 15 or 20
minutes. The broil part is only a couple of minutes.