Place the chicken breast in a shallow dish, and rub them with salt, pepper and Italian seasoning.
Melt 1 Tbsp butter or add oil in a large non-stick pan or skillet over medium-high heat and add in the chicken.
Sear until golden brown on both sides, about 5 minutes. The chicken doesn't have to be all cooked through, as we will continue to simmer it in the sauce. Set aside on a plate.
Add remaining butter/ghee to the preheated pan, together with onion and garlic, and sauté for 3-4 minutes.
Next, pour in the half and half, and bring it to a simmer. Stir well to deglaze the pan. Taste and season with salt and pepper.
Meanwhile, in a small bowl, whisk flour or cornstarch with a couple a Tbsp of water, until well combined. Add it to the sauce in the pan, and stir to combine.
At this point, it will begin to thicken. Return chicken to the pan, with all the juices, then gently add in the cherry tomatoes.
Continue to simmer until chicken is cooked through and cherry tomatoes are burst
Garnish with fresh chopped basil and serve immediately. Enjoy!