In a large mixing bowl, add lemon cake mix, eggs, melted butter, lemon zest and mix until combined. Do not over mix!
If dough is too crumbly and not coming together, mix in some water. Add 1 tablespoon at a time.
Cover bowl and chill dough in fridge for 20-30 minutes.
Scoop out small portions of the dough and form balls. If dough is too sticky, you can chill for a bit longer or oiling your hands also helps.
Place balls on a cookie tray, lined with parchment paper.
Press your thumb to make indentations in the center OR you can use the back of a wooden spoon and even the round bottom of a measuring spoon for a much professional appearance.
Now you have 2 options: You can spoon ¼ teaspoon of raspberry preserves or jam in the center right now and bake OR you can bake the cookies first without any jam and then fill the centers with jam, once they cool. If you go with the second option, please note that when you remove the cookies from the oven, the indentations are not going to be that deep anymore. Just press the back of a wooden spoon or the round bottom of a measuring spoon into the center again. You must do this quickly before the cookies have a chance to cool completely.
Bake at 350 degrees F for 8-10 minutes or until cookies are firm along the edges and a little spread out.
Allow the cookies to cool fully and enjoy.