Thumbprint Cookies

Bahan-bahan (20 porsi)

• ¼ cup unsalted butter (softened)
• ¼ cup shortening
• ¼ cup brown sugar (firmly packed )
• 1 egg (divided)
• 1 teaspoon vanilla extract
• 1 cup all-purpose flour (all purpose)
• pinch salt
• 1 cup finely chopped walnuts
• raspberry jam (seedless)