Whisk flour and salt together, combining well. Pour cream into a pot and whisk in the flour breaking up all lumps. Cook the mixture over medium heat, stirring constantly with a wooden spoon until mixture thickens, pulls from the sides of pot forming a ball. When ball of dough completly pulls from sides, remove from heat. Transfer to a mixing bowl and let cool to room temp. (Stirring will help cool a bit quicker)
When dough is cooled to room temp. whip mixture, adding butter and cream cheese until thoroughly combined. Continue to whip while carefully adding powdered sugar. Add vanilla, combine thoroughly. Works well with all types of cake recipes.