01 - Preheat oven to 350°F and line a baking sheet with parchment paper.
02 - Combine cranberries, sweetener, lemon juice, and water in a small saucepan. Cook over medium heat, stirring, until cranberries burst and mixture thickens, about 5 to 7 minutes. Mash cranberries and allow mixture to cool completely.
03 - In a large bowl, cream the softened butter and sweetener until light and fluffy. Beat in the egg and vanilla extract until well combined.
04 - Add almond flour, coconut flour, baking powder, and salt to the bowl. Mix until the dough is formed evenly.
05 - Divide the dough into two equal portions. Roll each portion between two sheets of parchment paper into a 1/4-inch thick rectangle.
06 - Evenly spread half of the cooled cranberry mixture onto each dough rectangle, leaving a small border around the edges.
07 - Carefully roll each dough rectangle into a log using the parchment paper to assist. Place logs in the freezer for 10 minutes to firm.
08 - Remove logs from freezer and slice into 1/2-inch thick cookies. Arrange slices on the prepared baking sheet.
09 - Bake for 12 to 15 minutes until edges are lightly golden. Allow cookies to cool on the baking sheet before serving.