For a short, easy run — honestly, often nothing. If you're heading out within an hour of waking or after a normal meal a few hours ago, you've usually got plenty in the tank already.
If you do feel you need something, keep it small and simple: a banana, a slice of toast, a handful of something easy to digest, eaten 30–60 minutes before. The goal is light energy, not a feast — a full stomach is a recipe for a stitch and a sluggish run.
This is one of those areas the running industry overcomplicates. As a beginner on short runs, you don't need gels, special drinks, or a fuelling strategy. That stuff matters at much longer distances, not yet.