Place frozen peaches, frozen banana slices, Greek yogurt, almond milk, honey (if using), and vanilla extract into a high-speed blender.
Blend on low speed for 10-15 seconds to break up the frozen chunks, using the tamper if your blender has one to push ingredients toward the blades.
Increase to high speed and blend for 30-45 seconds until completely smooth and thick, stopping to scrape down sides if needed. The mixture should be very thick, like soft-serve ice cream. Add 1 tablespoon more milk only if the blender won't turn.
Taste and adjust sweetness if desired, blending briefly to combine any additions.
Pour the smoothie into a chilled bowl, using a spatula to scrape every bit from the blender.
Working quickly, arrange granola, sliced almonds, and fresh berries on top in sections or patterns.
Serve immediately with a spoon and enjoy while cold and thick.