I have tons of trouble with portion control when I cook. So, when I make a recipe that results in 4 servings, I try to immediately weigh out one portion to use, and freeze the rest in single portion containers - I label them with the recipe name & date using masking tape & a black sharpie.
This method insures that us single folks don't get bored eating the same thing over and over! You will eventually have a freezer stocked with many varieties of homemade single portion entrees, labeled and ready to roll. You can also write the calorie or carb count on the label!