Add the Greek yogurt, maple syrup, freshly grated nutmeg, vanilla extract, and lemon zest to a large bowl. Using an electric mixer or whisk, beat the mixture for 3-4 minutes until it becomes noticeably lighter in color, fluffy, and increases slightly in volume. This whipping process aerates the yogurt to create an airy, cloud-like consistency and ensures the spices and vanilla are evenly distributed throughout.

Using a large trifle bowl or individual serving glasses, spread a thin layer of the whipped yogurt mixture at the bottom. Top with a layer of granola, followed by a generous portion of mixed berries. Continue alternating layers 2-3 times total, ending with a final layer of the yogurt mixture on top. Finish with a sprinkle of granola and arrange the most attractive berries on top for visual appeal. Layer carefully and gently to maintain clean, distinct stripes rather than blending everything together.

Cover and refrigerate the assembled parfait for a minimum of 30 minutes before serving, or up to 4 hours maximum. This chilling period allows the flavors to combine and meld together while keeping the granola from softening too quickly. Serve straight from the trifle bowl for a family-style presentation, or portion out individual glasses. For optimal texture with crispy granola, serve within a few hours of assembling.