In a medium bowl, add tomatoes, garlic, basil, mint, salt, pepper, red pepper flakes, and olive oil.: The bowl will smell instantly herbaceous and bright as the cherry tomatoes mingle with the extra virgin olive oil and minced garlic . You should notice a glossy sheen on the tomatoes and small bubbles of oil clinging to herb leaves. This maceration releases tomato juices, creating the base of the dressing. If you press a tomato quarter between your fingers it should give slightly, releasing flavorful juice. Avoid over mixing at this point which can break down tomatoes too much and create a watery salad.
Gently toss and let sit at room temperature for 1-2 hours.: As the mixture rests the aroma deepens and the oil takes on tomato and herb notes. You will see the liquid in the bowl turn a rosy hue, and the garlic softens in sharpness. The resting time allows the flavors to marry, which is why I often prepare this ahead. A common mistake is leaving them too long in a warm kitchen which can make the tomatoes collapse, so keep it in a comfortable room temperature spot, not in direct sun.
Cook pasta in well-salted water and drain well. Add the pasta to a large bowl and add some of the oil from the tomatoes and toss to combine.: The salted water seasons the pasta shells internally, and when cooked to al dente they will have a slight bite. After draining, the shells should feel springy, not mushy. Tossing immediately with a little of the tomato oil prevents sticking and infuses the pasta with flavor. If the pasta seems clumpy, add a touch more oil and gently separate with tongs. Overcooking is the most common error here, which yields a limp texture that will soak up too much dressing.
After the pasta cools for about 10-15 minutes, add the tomatoes and mix to combine. Add the cheeses and toss.: The brief cooling prevents the cheeses from melting completely, preserving their cubed texture. When you fold in the tomato mixture you should hear a soft swoosh, and the pasta will glisten with dressing. The cheeses will nestle into shells and pockets of oil, creating creamy bursts. If you add the tomatoes while the pasta is steaming hot the cheeses will collapse, so wait the short cooling period. Also, be gentle when tossing to keep tomato quarters intact.
Serve at room temperature.: Serving this salad at room temperature allows all the flavors to be pronounced and balanced. The mouthfeel should be varied across bites, with juicy tomato, tender pasta shells , and creamy mozzarella and fontina . If chilled too long the olive oil firms up and flavors feel muted, so let it sit at room temperature for at least ten minutes before serving if it has been refrigerated.
