Grease a 9" x 13" cake pan and set aside.

To make the base, beat together the butter, sugar and salt in a bowl until fluffy.

Stir in the flour until combined.

Remove 1 cup and set aside.

Press the remaining mixture into the prepared pan.

Bake in the centre of a 350 degree F oven until golden, about 17 minutes.

Let cool on a rack.

Spread the jam over the base.

In another bowl and using your fingertips, mix together the reserved butter mixture, ground almonds and almond extract until it forms pea-sized crumbs.

Sprinkle over the jam.

Sprinkle with the slivered almonds.

Bake in the centre of a 350 degree oven until golden, 30 minutes.

Let cool on a rack.