Make the ice cream: In a bowl, stir together ¼ cup milk and the cornstarch; set slurry aside. In a 4-qt. saucepan, whisk together remaining milk and the cream, sugar, molasses, and salt; bring to a boil over medium-high heat. Cook for 4 minutes; stir in slurry. Return to a boil and cook, stirring, until thickened, about 2 minutes.
Place cream cheese in a bowl and pour in ¼ cup hot milk mixture; whisk until smooth. Then whisk in remaining milk mixture. Pour mixture into a plastic bag; seal, and submerge in a bowl of ice water until chilled. Pour mixture into an ice cream maker; process according to manufacturer's instructions.
Make the praline: Combine pecans, brown sugar, molasses, butter, cinnamon, and salt on a foil-lined baking sheet and bake until bubbly and dark, about 12 minutes. Cool, roughly chop, and fold into churned ice cream.
Transfer ice cream to a storage container and freeze until set.
