Mix the Yogurt Base: In a medium mixing bowl, whisk together the plain Greek yogurt, pure vanilla extract, and chia seeds until completely smooth and velvety. If you prefer a softer, creamier oat bite, stir half of your rolled oats directly into this yogurt mixture and let it rest for 5 minutes.
Establish the Foundation: Spoon a generous, even layer of the vanilla yogurt mixture into the bottom of two clear glass tumblers or mason jars.
Create the Berry Ring: Press fresh raspberries gently against the inner glass walls. This creates that gorgeous bakery-style presentation where the vibrant red berries peek through the glass.
Add the Grain Layer: Sprinkle a light layer of dry rolled oats or sugar-free granola directly over the yogurt and berries.
Repeat and Build: Continue layering the yogurt, raspberries, and oats until your glasses are nearly full, ending with a smooth dollop of yogurt on top.
The Grand Finale Garnish: Crown each glass with a cluster of fresh, plump raspberries and a delicate dusting of toasted oat flakes or crushed granola. Serve immediately for maximum crunch, or chill in the refrigerator for 30 minutes for a richer, dessert-like texture!