These eggless custards are traditional in Italy, where they are called panna cotta.
In a small bowl, sprinkle the gelatin over 1/4 cup water. Let stand until softened, about 5 minutes.
In a saucepan, heat half-and-half and sugar over medium heat until sugar dissolves and mixture is hot but not boiling, 3 to 5 minutes. Remove from heat; stir in gelatin mixture, then buttermilk and vanilla. Pour into four 4- or 6-ounce ramekins or custard cups; chill until set, 3 hours.
Make the sauce: Puree raspberries, sugar, and lemon juice in blender. Strain through sieve into bowl, pressing with a spatula. Adjust consistency with water, if necessary.
To remove, dip each ramekin in hot water. Invert onto serving plate; shake gently until custard releases. Spoon sauce around custard; garnish with raspberries.
