Pre-heat oven to 350 degrees and lightly butter an 8x8 baking dish.
In a large bowl, whisk together flour, cinnamon, salt, and baking powder.
In the bowl of a stand mixer or in a large bowl with a hand mixer, cream together butter, brown sugar, and granulated sugar, and brown sugar until light and fluffy. Beat in the egg yolk.
Slowly mix in the flour mixture into the butter mixture until just combined. Stir in sliced almonds.
Put jam in a small bowl and mix with a fork to loosen it up. Alternatively, you can put the bowl in the microwave for 15 seconds to heat and loosen.
Press half of the dough onto the bottom of prepared pan. With a spoon, spread the jam over the dough, leaving a ¼ inch border. Then sprinkle the remaining dough over the top and gently press it down.
Bake for 25-30 minutes, until golden. Let cool in pan before slicing into squares.