In a medium saucepan add butter over medium heat and cook until milk solids turn brown and butter has a light brown color.
Add sugar and stir until combined.
Add milk, cream, salt, vanilla and stir until combined.
Once mixture is hot, temper eggs yolks. Add some of the mixture to the eggs while constantly whisking. Then, add the eggs to the saucepan while constantly whisking.
Heat until temperature reaches 175 degrees.
Strain using a fine strainer. Place plastic wrap directly over the base and allow to cool to room temperature.