Combine milk, cream, sugars, cinnamon and salt in medium saucepan and place over medium heat, stirring occasionally, until mixture is steaming and sugars are dissovled. Meanwhile, whisk egg yolks in medium mixing bowl. Gradually whisk hot liquid into yolks, then scrape back into pan and cook over medium heat, stirring constantly, until mixture is thick enough to coat the back of a spoon. Strain and chill thoroughly.