Preheat the oven to 350 degrees Fahrenheit. Line a cookie sheet with parchment paper for easier cleanup later, or you can just use an ungreased cookie sheet.

Cream the butter and sugar together in a large bowl until light and fluffy using a standing mixer with a paddle attachment or a hand mixer. You can even make this batter by hand, but you will have to beat it for a long time.

Add the egg and vanilla. Mix to combine. In a medium bowl, mix the flour, baking powder and salt. Add to the butter mixture and mix just until combined. Do not over mix.

Divide the batter into 4 pieces. On a lightly floured surface, or right on the cookie sheet, shape each piece of dough into a 12 inches x 3/4 inch log.

Make an indentation in the center of each log. Fill the center of each log with about 2 Tablespoons of jam. I usually use seedless raspberry jam, but any jam will work in this recipe.

Bake in the preheated oven for 15-20 minutes, just until the edges are lightly golden.

Cool the cookies for about 10 minutes and then cut them on a diagonal into 3/4 inch pieces.