Look at any list of recipes and you’ll find at least one “sunrise”. Usually a base liquor, orange juice, and grenadine for the color effect.
I was looking for something to do with limoncello, and on a whim, mixed it with orange juice. It was plenty sweet, and I decided not to add the grenadine. I playfully commented that it looked like the “midday sun”, and the name stuck (in the Lair, at least). This is a pretty mild drink, considering that the limoncello is the only alcohol at about 25-30% ABV.
If it is too sweet, adding a bit of lemon juice (or lime) should give it a bit of pucker!
1 oz Limoncello
3 oz Orange Juice
(optionally add 1/4 or 1/2 oz Lemon juice or Lime juice, if you want some tartness)