Preheat oven to 350°F and grease or line an 8 x 8 inch square baking pan with parchment paper.
In a food processor, mix crust ingredients until butter is completely mixed in and mixture is crumbly. Reserve 1 cup for crumble. Pour the remaining into baking pan and press together to form crust and then press evenly across the bottom of the pan.
In a medium bowl, pour raspberries and toss in flour and sugar until evenly coated. Using a spoon, break raspberries down slightly, so that they are halved rather than whole. Add all remaining filling ingredients (except raspberry mixture!) to a bowl of a stand mixer and mix on high speed until smooth. Pour custard filling on top of crust. Spoon raspberries on top, adding dollops evenly across so that each piece you cut later should have a little bit of raspberry in the mix, like in the photos.
Sprinkle with the 1 cup of reserved crumble, evenly and completely covering surface. Bake for about 60 minutes until top is golden and middle is set. Let bars cool before cutting and serving.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.