Rinse chicken breasts under cold water and pat dry.
Rub chicken with olive oil and season all over with salt and fresh ground black pepper.
Preheat grill and prepare it for direct-heat grilling over medium heat.
Place strawberry vinegar in a wide microwavable bowl (I use a soup bowl) and microwave on high for 3 minutes. This reduces the vinegar.
Meanwhile, toss your chicken breasts on the grill, skin side down.
Scrape down the sides of the bowl with a spatula and microwave again for 3 minutes. Stir with the spatula. It should be thicker.
Microwave for one more minute, and the vinegar should be reduced into a glaze, about the consistency of honey.
Once the chicken has had about 5 minutes on the skin side, flip it, and continue cooking another few minutes (time will vary with portion size).
Remove chicken and brush strawberry glaze all over. Allow to rest for a few minutes, then slice diagonally and serve.
Notes
Tip: You can reduce many varieties of vinegar down to a simple sauce or glaze using this quick microwave method. Try it with balsamic, red wine, raspberry, or (my favourite) sherry vinegar.