You can find a lot of places to eat very easily. There are tons of restaurants at all prices with delicious food. I am only sharing my little tip to eat for cheap at lunchtime. This is all happening in calle Berlin.
For lunch – Calle Berlin, a dozen of restaurants with “menu del dia”
Many options with prices from S/13.00 and up. You can get a soup (courtesy soup as they call it), a starter and a main plus some juice. I love those, it’s cheaper than cooking at home.
I really like when I can sit at a little table outside rather than inside in the dark (it’s January at the time of writing, so summertime!). There are so many places to try, they usually have a few options to pick from.

At night, calle Berlin changes into bars and more vibrant nightlife.
Where to buy groceries in Miraflores
Vivanda and Wong
Those are my 2 go-to supermarkets. Some locals told me Wong is the oldest in the city and is a bit more expensive. It’s also bigger than Vivanda.
You will also find lots of small shops very useful for quick top-ups of snacks, bread, water, etc.
Mercado Nº 1 de Surquillo
For vegetables and fruits go to Mercado Nº 1 de Surquillo.
Bonus: You will find a good cake place nearby, the name is Napoleon.