1 Cream The Butter And Sugar On High Speed For About 3 Minutes. 2 Separate The Eggs. Add The Yolks And Vanilla Extract To The Butter Mixture. If Using Nuts Place The Egg Whites In A Shallow Dish On The Side And Whisk Them Until Bubbly And Frothy (The Egg Whites Will Be Used To Keep The Nuts On The Cookies). 3 Add The Flour And Salt. Mix Until Just Combined. Place The Dough In The Fridge For 30 Minutes And Preheat The Oven To 350F. 4 Roll The Dough Into Balls About 1 Inch In Diameter. If Using Nuts, Dip The Balls Into The Egg Whites Then Roll Them Into The Nuts Until Covered. Place The Balls On Parchment Lined Cookie Sheets. 5 Press Down With Your Thumb To Make A Small Well In The Center Of The Cookie. Do Not Press Too Hard Or The Cookie Will Fall Apart. Fill With 1/2 Teaspoon Of Jam. 6 Bake For 12-15 Minutes Or Until Slightly Firm. Allow To Cool For A Few Minutes On The Cookie Sheet To Firm Up Before Moving Them To A Wire Rack To Finish Cooling.