Instructions

1. Preheat oven to 325. Butter a 9×9-inch or 7×11-inch baking pan and line with parchment paper.
2. In a small bowl, stir together the almond preserves and rum. Set aside.
3. Using a stand mixer, cream together the butter and sugar on high speed. Beat in the almond extract. Add the flour and salt and mix together on medium speed until flour is just incorporated. Transfer 1 cup of dough to another small bowl and add the crumbled almond paste. Use fingers to mix together until small clumps begin to form. Mix in 1/4 cup sliced almonds. Put mixture in refrigerator to chill for a few minutes.
4. Use hands to press the remaining dough in the bottom of the prepared baking pan. Spread preserves evenly over the dough. Crumble the slightly chilled almond paste mixture over the preserves and sprinkle the remaining 1/4 cup almonds on top. Press the topping lightly into the preserves.
5. Bake until shortbread bars start to brown and become golden, about 50 minutes. Cool for at least 1 hour before cutting into squares.