In a small bowl, stir together cake flour, white whole wheat flour, and jasmine tea; set aside.
In a medium bowl, combine butter and cream cheese. Beat with an electric mixer on medium to high speed for 30 seconds. Add sugar and salt. Beat until combined, scraping side of bowl occasionally. Beat in egg white and vanilla until combined. Beat in as much of the flour mixture as you can with the mixer. Using a wooden spoon, stir in any remaining flour mixture. Wrap and chill dough about 4 hours or until easy to handle.
Preheat oven to 375°F. Shape dough into 1-inch balls. Place balls 1 inch apart on ungreased cookie sheets lined parchment paper.
Bake for 10 to 12 minutes or just until edges and bottoms are lightly browned. Cool on cookie sheets for 1 minute. Transfer cookies to wire racks; cool. If desired, sprinkle with powdered sugar.
Tip: We do not recommend using sugar substitute in this recipe.
To store, layer cookies between waxed paper in an airtight container. Cover; seal. Store at room temperature for up to 1 day or freeze for up to 1 month.