Combine the milk in a large heavy saucepan and bring to a boil. Remove from heat and mix in vanilla extract and salt.

Whisk egg yolks and remaining half cup of sugar and baobab fruit powder in a medium bowl. Gradually whisk in about 3/4 cup of the hot milk mixture. (the point of this is that you want to slowly heat the egg mixture to the same temperature as the milk mixture so that the eggs don’t cook when you add them fully to the milk mixture.)

Stir the now warm egg mixture into the saucepan, turn the heat back on to low and add the heavy whipping cream. Continue cooking, stirring constantly, until the custard thickens (a path should be left behind when you draw your finger across the back of the spoon). Don’t let it boil.

Strain the custard through a sieve.

Stir the carmel (and nuts if desired).  It doesn't need to be mixed. You can use a spoon and 'swirl' in the carmel.
 
Chill overnight if possible, but at least 2 hours. Makes 3-1/2 cups.