Place tea bag in a small cup or bowl. Add boiling water and steep for 10 minutes. Discard tea bag and let tea cool completely.
In a separate bowl, make flax egg by combining ground flax meal and water. Stir gently and let sit for 5-10 minutes.
Preheat oven to 400°.
Using a stand mixer or wooden spoon, cream butter and sugar until light and fluffy. Mix in flax egg and cooled tea.
In a separate bowl, whisk flour, cinnamon, cardamom and salt; gradually beat into creamed mixture.
Spoon level tablespoons of dough 2 inches apart on ungreased baking sheet. Flatten dough by gently pressing with the bottom of a glass.
Bake for 10 minutes or until light brown. Move to wire racks to cool completely.
In a small bowl, stir 1 tbsp of powdered sugar and cinnamon and dust over first 12 cookies.
In a second small bowl, combine remaining 3 tbsp of powdered sugar, lemon juice, and lemon zest. Stir to combine. Spoon onto remaining 12 cookies. Be sure cookies are completely cooled before adding frosting, otherwise it will melt and drip off.
Enjoy!