Preheat oven to 350 degrees F. Line an 11x7-inch glass baking dish with foil or parchment paper forming a sling with enough foil/parchment to overhang the sides at least 2-inches. This will allow ample area to grab the sling when it is time to remove the cookie bar from the pan. Spray the pan and sling with cooking spray or grease.
Combine flour, corn starch and salt in a medium bowl; whisk to blend.
Using an electric mixer, beat butter in large bowl until light and fluffy. Add 1/2 cup sugar and beat until light. Beat in vanilla and almond extracts. Add flour mixture and beat on low speed until the dough begins to come together. Mix in 3/4 cup almonds.
Press dough onto bottom of prepared dish. Pierce all over with fork. Bake until just firm to touch and light golden brown, about 25-35 minutes.
Stir jam in small saucepan over medium-low heat, until melted and hot (this can also be done in the microwave). Spread jam over warm cookie crust. Return to oven and bake until jam bubbles in the center, about 15 minutes. Cool completely on rack.
Combine 1 1/2 teaspoons sugar and 2 Tablespoons almonds in a small bowl. Once bars are cooled, sprinkle over the jam layer.
Using the foil/parchment as an aid, lift entire cookie from dish, and trim edges. Cut into 2x1-inch bars.
Can be made 2 days ahead. Cover and store in single layer in refrigerator.