Place raspberries and brown sugar in a blender; cover and process until pureed. Press through a sieve; discard seeds.
In a small saucepan, combine the raspberry puree, orange juice, cornstarch and orange zest. Cook and stir over medium heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Remove from the heat; cool.
In eight parfait glasses, layer half of the raspberry sauce, berries, granola and yogurt. Repeat layers. Sprinkle with additional brown sugar if desired. Serve immediately.