Add cleaned, whole strawberries to a sauce pot with the green steams removed. Cook on medium-low heat with water and smash as strawberries soften. Smash until strawberries are fully cooked and mushy.
Take strawberries off the heat, add maple syrup and chia seeds. Mix together and cool at room temperature for at least 20 minutes. Then refrigerate to continue to thicken.
To make the overnight oats, add rolled oats, cinnamon, sugar, vanilla, chia seeds, and milk to a bowl. Let sit and refrigerate for 10 minutes to start thickening.
Assemble parfaits in mason jars by layering overnight oats then strawberry chia seed jam then Greek yogurt. Top with fresh diced strawberries.