Instructions

To Make the Crust and Crumb Topping:

1. Preheat the oven to 350°F.  Put a long piece of parchment paper in the bottom of a 9-by-13-inch glass or light-colored metal baking pan, letting the parchment extend up the two short sides of the pan and overhang slightly on both ends.  (This makes it so much easier to remove the bars from the pan after they have baked and cooled.)  Butter or spray the parchment.
2. Put the flour, brown sugar, oats, salt, baking powder, baking soda, and cinnamon in a food processor or mixer and pulse in short bursts until combined.  Add the (softened) butter and pulse until loose crumbs form.
3. Reserve about half of the mixture and set aside.  (You want to make sure that you have enough for the top layer so that the middle layer of raspberries are mostly covered.)  Pour the rest of the mixture into the prepared pan and use your hands or the back of a large spoon to push the crust into an even layer at the bottom of the pan.  The crust should touch the sides of the pan.  Bake until golden brown, 12 to 15 minutes.  Remove from the oven and let the crust cool.  Keep the oven on while you make the raspberry filling.

To Make the Raspberry Filling: 

1. In a medium bowl, whisk the sugar, lemon zest, cinnamon and flour together.  Add the raspberries, lemon juice and melted butter and use your hands to toss gently until the raspberries are evenly coated.

Assemble and Bake the Bars: 

1. Spread the raspberry filling evenly on top of the cooled bottom layer of crust.  Sprinkle the reserved crust mixture evenly on top of the filling.
2. Bake for 35 to 45 minutes, rotating the pan every 15 minutes, until the top is golden brown and the filling starts to bubble around the edges.
3. Remove from the oven and allow to cool completely, then cut into squares and serve.  The bars can be stored in the refrigerator in an airtight container for up to two days, and surprisingly, these bars taste extra-amazing cold (the raspberry filling really comes together when cold).