Melt butter in a large saucepan over medium high heat. Add brown sugar and salt and whisk steadily until dissolved.
In a small bowl, combine cornstarch, 1/2 cup of milk and yolks. Whisk until smooth.
Pour remaining milk and cream into pan with sugar mixture. Bring to a simmer over medium-high heat, stirring constantly.
Pour 1 cup of milk mixture in a very slow stream into bowl with cornstarch mixture, whisking constantly and vigorously. Pour cornstarch mixture back into pan, increase heat to high, bring to a boil and whisk until thickened and smooth, 2 to 3 minutes. Remove from heat and whisk in vanilla. Strain pudding through a fine-mesh sieve into a large measuring cup or bowl. Divide among 8 1-cup ramekins or custard cups.
Cover each pudding cup with plastic wrap, pressing lightly so it touches surface of pudding. Refrigerate for at least 6 hours, or until thoroughly chilled and set. Serve with heart-shaped spice cookies.