Preheat the oven to 400°F. Place grapes onto a baking sheet. Drizzle the balsamic vinegar and olive oil over the grapes, and sprinkle with fresh rosemary and salt/pepper to taste. Toss and roast in the oven for 30 minutes, or until the grapes become soft and wilted.
To make the whipped feta, add the feta, cream cheese, and lemon juice to a food processor (or blender) and blend until smooth.
Serve the roasted grapes alongside the whipped feta. You can add a few pita chips for dipping or spread a serving of the whipped feta on a piece of toast and top it with the roasted grapes. Enjoy!