Preheat the oven to 350°F. Line an 8×8 baking dish with parchment paper.

Add all shortbread ingredients to a food processor. Pulse until well combined. You should be able to press mixture together with your fingertips. Press mixture into an even layer on bottom of the prepared baking dish. Prick the shortbread a few times with a fork. Bake for 12 minutes.

While shortbread is baking, prepare the jam filling. To a small saucepan over medium heat, stir together raspberries, chia seeds, maple syrup, and lemon zest. Let jam come to a low simmer then cook for 5 minutes until berries have broken down. In a small bowl, whisk together 1 tbsp corn starch and 1 tbsp water. Whisk corn starch slurry into jam. It will start to thicken immediately, remove from heat. Once shortbread is done baking, spread over jam into an even layer. 

In a small food processor, pulse together all streusel ingredients until combined. Sprinkle streusel over jam filling. Bake for 22-25 minutes until top is light golden brown. Allow bars to cool for 10 minutes before slicing. Top with a drizzle of peanut butter.