In a medium pot, melt 2 tablespoons of butter over medium heat. Add the garlic and saute for about 30 seconds.
Add the chicken broth and half and half. Bring to a boil, then add the pasta shells. Keep it at a gentle boil and cook uncovered according to the package directions, stirring occasionally to prevent pasta from sticking to the bottom of the pot.
When the pasta is done, remove the pot from the heat. Stir in the remaining butter, parmesan, parsley, and lemon juice. Season to taste with salt and pepper.