To toast the almonds, spread them on a baking sheet and toast them in a 350ºF/180ºC oven for about ten minutes, stirring them midway during baking. Let cool completely before grinding in the food processor.
If you don't have a food processor, you can grind the almonds and flour in a blender, pulsing them until they're in smaller pieces. If you don't have a square cake pan, a similar pan that's about the same size would work, such as a springform or tart pan, although the Sbrisolona will be thicker as round pans have less capacity. I have seen recipes where people pat the mixture directly onto a parchment-lined baking sheet into a rough approximation of the size of a 9- 10-inch (23-25cm) pan, and baking it that way, although I haven't tried it. If you do, let us know in the comments how it works out.
Some variations include using hazelnuts instead of almonds, adding some anise seeds (perhaps about 1 teaspoon), or a bit of cinnamon to the dough. For more crunch, replace the 1/4 cup (45g) of brown sugar with granulated sugar, for a total of 3/4 cups (150g) granulated sugar. The brown sugar adds a touch of toffee-like flavor, but does make the Sbrisolona slightly softer. If you have granulated brown sugar, such as turbinado, demerara, or another
raw cane sugar, use that.
One tip from my friend Judy Witts Francini, of
Divina Cucina, is to splash the hot Sbrisolona with
grappa, which she says "gives it a nice kick." I'm sure it does!