Spray a 9-by-13-inch baking pan with nonstick cooking spray; set aside.
In a large bowl, beat the butter and sugar for 5 minutes with an electric mixer. Add the eggs, and beat for 2 more minutes. Add the flour and almond extract, and mix to combine.
Spread the batter in the prepared pan, and sprinkle with the cranberries.
Bake for 40 to 45 minutes, or until a cake tester inserted in the center comes out clean. Sprinkle the toasted slivered almonds on top. Return to the oven, and bake for another 5 minutes, or until the nuts are golden.