Preheat oven to 325 degrees F.
Microwave the unsweetened chocolate baking squares, semi-sweet chocolate baking squares, and 1/4 cup butter in a microwave-safe on high in 30-second intervals, stirring between each, until completely melted, about 2 minutes total. Set aside and let cool.
Beat the cream cheese and remaining 1/4 cup butter at medium speed with an electric mixer until creamy. Gradually add 1/2 cup sugar, beating well until combined. Add in 2 eggs, one at a time, beating until blended. Stir in 1 tsp vanilla and saffron. Fold in 2 Tbsp flour and set aside.
Beat the remaining 4 eggs in a large bowl at medium speed.
Gradually add the remaining 1/2 cup sugar, beating well.
Add in the melted chocolate mixture and 2 tsp vanilla. Beat the mixture until well blended. Fold in pecans (if desired).
Combine the remaining cup of flour, baking powder, and salt. Fold into the chocolate batter until combined.
Reserve 3
cups chocolate batter; spread remaining batter evenly in a greased 9 x
13-inch pan. Pour saffron cream cheese mixture over batter and spread
evenly. Top with reserved 3 cups chocolate batter; swirl mixture with a
knife.
Bake for 40-45 minutes. Let cool completely, then cut brownies into squares. Dig in!
