MAKE IT
Step 1
Place cornstarch and baking soda in large, heavy-duty saucepan. Add evaporated milk and water. Stir with wire whisk until dissolved. Add brown sugar. Cook over medium-low heat, stirring constantly with wire whisk and/or, heat-resistant rubber spatula, until sugar melts and thick, smooth consistency is reached, approximately 30 minutes. You will see bottom when spoon is drawn across the bottom of pan. Stir in vanilla extract and nuts until blended.
Step 2
Pour into dessert dishes. Refrigerate for at least 2 hours. Top each dessert with walnut half, if desired.