1. Cut a slit into the sides of the figs. Fill the slit with blue cheese and sprinkle with a pinch of rosemary.
2. Cut the prosciutto slices in half and wrap one-half slice around each fig. Brush with olive oil and grill over low heat until warmed through, about 4 minutes.
3. Remove from the heat and arrange on a serving dish, sprinkle with hazelnuts and serve warm.