In a small saucepan over medium-low heat, melt the butter with ½ cup Thai tea mix and let it come to a boil.
Pour into a glass jar or liquid measuring cup. Let the mixture steep for 10 minutes, then strain the tea leaves and pour butter in a medium bowl.
Preheat oven to 350 degrees Fahrenheit.
Lightly spray a 9x13-inch metal cake pan with cooking spray and line with parchment paper, leaving a 2-inch overhang on the pan’s two long sides. Spray the parchment too.
In the medium bowl, mix butter, brown sugar, vanilla and 2 eggs until well-blended.
In a separate bowl combine flour and salt. Fold this into the butter mixture until all combined.
Spread ⅔ of the blondie batter into the 9x13 pan.
Spoon cream cheese mixture over batter and spread evenly.
Spoon the remaining ⅓ of the original batter in dollops on top of the cream cheese layer and swirl with a knife.
Bake for 25-30 minutes, or until a skewer inserted into the center of the blondies comes out with a few crumbs attached. Cool completely on a wire rack before slicing.