Store in an airtight container in the fridge for 3 to 4 days. The pasta is best shortly after making, when the sauce is creamy and satiny.  I actually prefer leftovers cold over warmed up. If you want to reheat, heat the leftovers in a skillet over medium-low heat. Add a splash of water as needed to thin and toss frequently. If needed, perk the pasta up with some fresh lemon zest and/or juice.