Pre-heat your oven to 350°F.
In a large bowl, combine nut butter, sugar, and egg until well combines and a dough forms.
Shape dough into balls, about 2 tablespoons each. Roll in additional granulated sugar or green sanding sugar. Place on a lined cookie sheet, about 2 inches apart.
Bake 8 to 10 minutes or until edges are light golden brown.
Immediately press 1 unwrapped mini creme egg or 3 mini eggs in the center of each cookie.
Allow to set for 5 minutes or so before removing from cookie sheets to cooling rack.