Preheat oven to 350°F and prepare a 9x13-inch baking dish.

Cream together softened butter and 1/2 cup sugar until fluffy. Mix in egg yolks one at a time. Add flour and salt and mix just until combined.

Press dough evenly into the bottom of the baking dish. Bake for 13–15 minutes or until edges are golden.

While crust bakes, beat egg whites until stiff peaks form. Gradually add 1/2 cup sugar, beating until glossy. Fold in chopped nuts.

Spread jam over the baked crust. Spoon meringue mixture on top and spread gently to the edges.

Bake for 18–20 minutes, or until meringue topping is lightly golden.

Let cool for 10–15 minutes before slicing. Allow to fully cool before removing from the pan.