Cream together the softened butter, Crisco, and sugar until light and fluffy.

Add the egg and egg yolk to the mixture and combine well.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Stir in the almond flavoring.

Spread the dough evenly onto a 13 x 9-inch cookie sheet.

In a small bowl, beat the egg white until frothy.

Brush the frothy egg white over the dough.

Sprinkle the slivered or sliced almonds evenly over the egg white layer.

Bake in a preheated 350°F (175°C) oven for 12 to 15 minutes, or until the edges are light brown.

Remove the cookie sheet from the oven and let it cool slightly.

Cut the baked cookie into squares.

Turn off the oven and place the cookie sheet back in the oven.

Leave the cookie sheet in the oven overnight to dry out and become crisp.

Store the Swedish Toast Cookie Bars in a tightly sealed container to maintain their crispness.