These Key-lime-pie-meets-cheesecake bars are the perfect mashup of creamy and tangy flavors, offering just the right amount of sweetness. Use fresh-squeezed Key lime juice if Key limes are in season. If not, bottled Key lime juice works well. No Key limes? No problem. A 1-to-1 mixture of regular lime juice and lemon juice will give you a similar floral flavor.