Prepare pasta according to package directions to al dente and strain.
In a large pot, pour in the creamy past mix and 1/4 cup of milk and stir until all the mix has dissolved and there is no powder left.
Add the rest of the milk and the lemon juice and bring to a boil and boil for one minute, stirring frequently.
Lower temp to low and add in the chopped spinach and any additional add ins and stir to combine.
Add in the cheese and stir well.
Add the pasta back into the pot of sauce and toss to coat.
Serve hot and enjoy!