1/2cupjamany favorite. Additional options in post above.
Instructions
Preheat your oven to 350 degrees.
In a mixing bowl, beat the the butter and sugar for about 2 minutes until fluffy.
Turn the mixer down to low, and add in the egg yolk, and vanilla. Beat well.
With mixer still running on low, sprinkle in the remaining dry ingredients one at a time, in the order they are listed. Hold off on the jelly and nuts at this point! Dough will be stiff.
Grab about a tablespoon of dough and roll into ball. Continue until you have rolled them all. If dough seems overly soft and warm, chill the balls for 10-15 minutes.
If you are using nuts, now is the time to roll the balls into the finely chopped walnuts. With no egg, you roll firmly to gently press the nuts slightly into the ball, OR roll in the whipped egg white first, then roll in the nuts.
Place on a cookie sheet and press your thumb in the center to make an indentation for fillings.
Use about a 1/2 teaspoon-1 teaspoon of jam per cookie. No exact science here, just fill your holes up...but don't overfill...the jam will spill out while it bakes and it does not look as pretty.
Bake for about 10 minutes. Cookies should still be soft, but firm up perfectly as they cool.