Preheat oven to 350 degrees F (175 degrees C). Prepare 2 loaf pans with cooking spray.
Beat cream cheese, 3/4 cup sugar, and cornstarch together in a small bowl until creamy and smooth.
Beat flour blend, pumpkin puree, 1 1/2 cups sugar, eggs, milk, butter, baking powder, cinnamon, and salt together in a large mixing bowl with an electric hand mixer set to Low until you have a thick batter.
Pour about 1/4 of the batter into the bottom of each prepared loaf pan. Spread 1/2 the cream cheese filling over each batter portion. Divide remaining batter between the two pans and spread into an even layer.
Bake in the preheated oven until a toothpick inserted into the center of the cake, not the filling, comes out clean, about 1 hour.