To make the marinade, in a small bowl or mason jar, whisk together olive oil, balsamic vinegar, garlic, chopped basil, onion powder, dried oregano, red pepper flakes, salt and pepper.: Warm scents of garlic and basil will rise as you mix, and you should notice the olive oil take on a darker, glossy sheen from the balsamic vinegar . This step is where flavors begin to marry, so whisk until the mixture looks uniform and slightly glossy. Pay attention to the aroma, it should smell balanced, not sharp with raw vinegar. A common mistake is under-mixing which leaves pockets of vinegar, causing uneven acidity. If you detect sharpness, let the marinade sit for five minutes before adding to the salad so flavors calm.
In a large bowl, add your sliced tomatoes and mozzarella balls and drizzle the olive oil mixture over top. Toss together until everything is coated, cover with plastic wrap and let everything marinate in the fridge for up to 2 hours or overnight (see notes for best marinating time).: As you pour, you will hear a soft, liquid hiss as the oil glides over the tomatoes and mozzarella . Toss gently so the skins and cheese get evenly coated and glossy. Visual cues to watch for include an even sheen and tomatoes starting to glisten from their own juices mingling with the marinade. Avoid aggressively tossing which can bruise the delicate mozzarella and burst more tomatoes than you want.
When ready to serve, take the salad out of the fridge about 30 minutes to an hour before so that the olive oil can come back to room temperature and return to liquid form. Add a little more fresh basil and season as needed right before serving. Enjoy!: During marinating, fragrances intensify and textures shift slightly as the balsamic vinegar softens the edges of the cheese and the tomatoes relax. You will notice juices pooling, which is normal and flavorful. Chill for at least two hours to let the flavors meld; an error here is rushing straight to the table, which yields a less integrated taste. If planning ahead, I often prefer about six hours of marinating for peak balance.
When ready to serve, take the salad out of the fridge about 30 minutes to an hour before so that the olive oil can come back to room temperature and return to liquid form: Cold oil firms up in the fridge, so bringing the dish closer to room temperature releases aromas and restores the silky mouthfeel. Watch the salad during this time, you should see the oil loosen and the scents become more pronounced. A common oversight is serving it straight from the fridge, making the texture heavy and muted instead of bright. Allowing the salad to warm slightly makes each bite more aromatic and flavorful.
Add a little more fresh basil and season as needed right before serving: Finish with torn or sliced fresh basil and a final micro-adjustment of salt and pepper to brighten flavors. This final touch refreshes the color and amplifies aroma. Look for lively green flecks of basil and taste a forkful to judge seasoning. A mistake to avoid is over-salting; adjust gradually and taste in between. Serve while the salad still smells fresh and vibrant for the best experience.