Hungarian Strawberry Pastry Bars

Ingredients (12)

• 5 cups all-purpose flour
• 1 cup plus 3 tablespoons sugar, divided
• 4 teaspoons baking powder
• 2 teaspoons baking soda
• 1/8 teaspoon salt
• 1-1/4 cups shortening
• 4 large egg yolks
• 1/2 cup sour cream
• 1/4 cup water
• 1 teaspoon vanilla extract
• 2-1/2 cups chopped walnuts, divided
• 1 jar (18 ounces) seedless strawberry jam