Add the frozen papaya chunks, frozen mango chunks, and passion fruit purée to your blender first, layering the frozen fruit on the bottom. This prevents the liquid from splashing and helps the blender process the frozen fruit more efficiently, creating a smoother blend.
Pour the Greek yogurt and milk over the fruit, then add the honey. The yogurt will add creaminess and a slight tang that balances the tropical sweetness, while the honey dissolves more easily when it contacts the cold fruit and liquid.
Secure the blender lid firmly and blend on high speed for 45-60 seconds, until the mixture is completely smooth with no visible fruit chunks and reaches a thick, creamy consistency. You should hear the blender motor working steadily without any grinding sounds, indicating the ice and frozen fruit have fully incorporated.
Stop the blender and check the consistency by tilting the pitcher slightly—the smoothie should flow slowly like soft-serve ice cream, not pour like juice. If it's too thick, add 2-3 tablespoons more milk and blend for another 10-15 seconds; if too thin, add a few more ice cubes and blend briefly.
Pour the smoothie into a tall glass, filling it about three-quarters full so there's room for any natural separation that may occur. The smoothie should have a vibrant peachy-orange color with a creamy, opaque appearance.
Give the smoothie a quick stir with a long spoon or straw before taking the first sip to recombine any settled fruit pulp with the yogurt base. Taste the smoothie and add an extra drizzle of honey if you prefer it sweeter, stirring well to incorporate.
Serve immediately while the smoothie is still cold and thick, as it will begin to separate and thin out as the ice melts. For the most authentic Panera experience, drink it within 5-10 minutes of blending for optimal texture and temperature.