In a medium mixing bowl, whisk together the chia seeds, oat milk, Meyer lemon juice, lemon zest, vanilla extract, and maple syrup.
Stir well to combine, making sure there are no clumps of chia seeds and the mixture is smooth.
Cover the bowl or transfer the mixture to a sealable container and refrigerate for 4-6 hours, or overnight, to allow the chia seeds to absorb the liquid and thicken into a pudding-like consistency. Top with the frozen raspberries. You can also let the pudding set up in the mixing bowl and once set, divide the chia mixture into 4 individual servings and top or layer each container with the ¼ of the frozen raspberries.
Enjoy as a nutrient-packed breakfast or a refreshing snack