Prepare ravioli (See Spinach and Ricotta recipe for details.) Cook in salted, boiling water until they are tender and float to the surface.
Heat butter and hazelnuts in pan over medium heat until the butter browns. Add broth and remove from heat. Drizzle over ravioli on plate and top with Parmesan cheese if desired.
Variation: Season filling with cinnamon and nutmeg instead of fresh sage.