In a medium bowl, combine the flour, salt, and baking soda. Set aside. Line 2 baking sheets with parchment paper. Also set aside.
In a bowl of an electric mixer fitted with a paddle attachment over medium/high speed, cream butter, cream cheese, and sugar until light and fluffy, about 2 minutes. Add eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Reduce the speed to low and add the flour mixture in 2 parts and mix until just combined. Fold the dough onto itself with a spatula to incorporate all the dry bits. Cover the mixing bowl with plastic wrap and place in the freezer for 30 minutes. This will allow the dough to firm up. While the dough chills, make the guava filling.