1. Preheat oven to 375 degrees F (190 C). Line a 13x9-inch baking pan with parchment paper. Reserve 2 small chunks of the butter and set aside (this will be for the streusel).
2. In the bowl of a standing mixer, combine the flour, salt and white granulated sugar. With the paddle attachment and the mixer on low, add the butter one piece at a time. Mix until it looks like wet sand starting to clump together (this is a great tip from Cooks Illustrated -- usually, or rather, always, recipes call for a mixture to resemble "coarse meal" which sometimes seems meaningless.).
3. Measure out half the mixture (about 1-1/4 cup) and set aside for the streusel. Press the rest of the mixture down into the baking pan with your hands, making sure it's as even as possible. Bake the shortbread for 14-15 minutes, until it is lightly brown.
4. In the meantime, combine the remaining flour-butter mixture with the oats, brown sugar, and nuts. Adding the butter you set aside earlier, rub the mixture together with your fingers until it creates large clumps and kind of adheres together, but still looks crumbly.
5. In a small bowl, mash up the raspberries a bit, then add the jam. Test for sweetness/sourness and add the lemon juice if it's too sweet (the lemon also keeps the raspberries a nice bright color). Mash it together. Pour the raspberry mixture over the shortbread and spread with a spatula.
6. Sprinkle the streusel evenly over the shortbread and raspberries.
7. Bake for 20-25 minutes, or until the filling is bubbling and the top is golden brown. Cool on a rack until room temperature or just warm, then cut into squares.

Labels: recipes, the sweet