Preheat oven to 350°F. Grease a 1-1/2 quart baking dish. In a medium-sized bowl, whisk eggs, milk, 3 tablespoons of the sugar and the almond extract. In the prepared baking dish, place 1 cup of the shredded croissant; sprinkle with 1/2 cup of the blueberries. Repeat three more times. Pour egg mixture on top, gently pressing down with a spoon to submerge blueberry-croissant mixture. Sprinkle with the remaining 1 tablespoon sugar and the sliced almonds; let stand for 20 minutes. Bake until top is browned and a knife inserted 1 inch from edge comes out clean, about 20 minutes. Serve warm.