To prevent splattering, remove skillet from heat and add tomato sauce, tomato paste, pinch of salt, chili flakes, oregano, basil, sweetener, and stir to combine.
Place back over heat and bring to a low simmer over medium-low heat. Once simmering, reduce heat to low and continue cooking for 10-15 minutes, stirring occasionally.
Cook pasta according to package instruction as this time. Then drain and set aside.
Sample pasta sauce and adjust seasonings as needed. Add more sweetener to balance and enhance the flavors or chili flakes for heat, salt for saltiness, or more herbs for depth of flavor. If too thick, thin with a little water.
Add the cooked drained lentils to the sauce and stir to combine. Then add pasta to the sauce and toss to coat.
Serve with any additional toppings such as red pepper flakes and fresh basil.