We had a lovely time in Lisbon and stayed at Luisa's apartment for 10 days. She was super helpful and gave us a lovely welcome (tips about the neighbourhood, normal costs and culture). The flat is super central and the perfect accommodation for a couple. You'll find everything to cook easy meals. However, there is an abundance of food shops, restaurants and bars close by – so you don't have to cook at all ;)
For people with light sleep: you may wake up at night from time to time ... but if you want to experience Lisbon aside touristy attractions this lively neighborhood will give you a good start. Additionally, the view from the kitchen window is beautiful... keep that in mind when you climb the steep stairs to the flat ;)