Pour half-and-half into 1 1/2-quart saucepan. Sprinkle gelatin evenly on cold half-and-half. Let stand 10 minutes.
Heat half-and-half mixture over medium-high heat 5 to 7 minutes, stirring constantly, until gelatin is dissolved and mixture is just beginning to simmer (do not allow to boil). Remove from heat.
Stir in sugar, vanilla and salt until sugar is dissolved.
Pour mixture into four 1/2-cup ramekins or 6-oz custard cups. Cover with plastic wrap and refrigerate about 4 hours or until set.
Meanwhile, make raspberry sauce. In 1-quart saucepan, mix sugar and cornstarch. Stir in water and raspberries. Cook over medium heat, stirring constantly, until mixture thickens and boils. Boil and stir 1 minute. Strain sauce through a strainer into bowl to remove seeds if desired. Serve sauce warm or cool. Store covered in refrigerator up to 10 days.
When ready to serve, run thin knife around edge of each panna cotta. Dip bottom of each ramekin into bowl of very hot water for 5 seconds. Immediately place serving plate upside down onto each ramekin; turn plate and ramekin over and remove ramekin. Serve with sauce.