Whisk balsamic vinegar and honey in a small sauce pot and set the heat medium. Bring the mixture to simmer.
Once it starts to simmer, turn the heat down to medium-low. Let vinegar gently simmer, stirring every minute or so, until the mixture thickens enough to coat the spoon. (It will take 7-10 minutes but please note, that it will start to thicken fast during the last couple of minutes so keep an eye on it.)*
Caprese Salad:
Slice tomatoes and mozzarella cheese as close to the same thickness as you can.
Lay out the tomato and mozzarella slices, alternating them, either in a circle or in a couple of lines.
Either mince the basil leaves or tuck them whole in between the tomatoes and cheese. Try to spread them around evenly.
Once the balsamic reduction cools to room temperature, drizzle it all over the tomatoes and mozzarella. (Serve remaining balsamic reduction on the side so your guests can serve themselves more if they wish.)
Notes
Other tomato options: if you can't get tomatoes on a vine, you can also use heirloom tomatoes or Roma tomatoes. *Balsamic reduction thickness: Please remember that balsamic reduction is a lot thicker when it cools than when it is hot. So don't wait until the reduction reached the thickness you want, but rather until it coats the spoon.)Storing balsamic reduction: Store balsamic reduction in a glass jar with an air-tight lid. Store it in the refrigerator for up to 3 months. You may need to reheat it for a few seconds before using. Storing caprese salad: you can store it in an air-tight food storage container, in the refrigerator for only about a day. After that, tomato wilts too much.