In medium bowl, cream butter and sugar with electric mixer until light and fluffy. Add vanilla extract and lemon zest.
In separate bowl, whisk together flour and salt; gradually add to butter mixture. Cover dough; chill at least 2 hours, or until firm.
Preheat oven to 375°F. Shape dough into 1/2-inch balls and place 1 inch apart on parchment-lined baking sheets. Lightly flatten half the balls with bottom of a juice glass to create “bottom” layer of button. Sprinkle rounded button tops with decorative sugar.
Bake cookies 8 to 10 minutes, until lightly brown on bottom edges. Remove cookies to wire rack; cool completely.
Once cooled, spread bottom cookies with 1/4 teaspoon apple cider jelly; place cookie top on jelly. Store unfilled cookies in airtight container, in refrigerator, for up to 1 week, and filled cookies for up to 3 days. Bring cookies to room temperature before serving.
*Apple cider jelly is available from many online gourmet retailers. Apple jelly or another preserve may be substituted. Recipe for homemade jelly is below:
Combine 6 cups fresh apple cider, 4 cups sugar and 1 box (1 3/4 ounces) sure-jell dry, sugar-free pectin in saucepan over medium-high heat. Bring mixture to boil; stirring constantly. Reduce heat; simmer 10 minutes, stirring intermittently. Remove from heat; skim off any foam; pour into clean sterilized jars. Refrigerate to set (or process according to canning instructions).