In a small bowl, mash the raspberries with a fork until they resemble a jam-like consistency.

Stir in the chia seeds and maple syrup. Let the mixture sit for about 10 minutes to allow the chia seeds to soften.

If desired, toast the bread slices.

Spread peanut butter on one slice of bread and the raspberry chia jam on the other. Press the slices together to form a sandwich. Serve.

Meal Prep Note: You can make the raspberry chia jam in advance and store it in an airtight container in the fridge for up to 5 days. Assemble sandwiches fresh for best texture, or prep ahead and store tightly wrapped in the fridge for up to 24 hours.