Reserve ¼ cup (60 mL) yogourt. In a blender, add remaining yogourt, raspberries, milk and lemon zest. Blend until smooth; pour into 4 bowls.
Top each bowl with dollop of reserved yogourt; swirl in a decorative pattern. Sprinkle on granola, raspberries and crumbled graham crackers. Serve immediately.
Substitute chopped strawberries or blueberries for raspberries.