Add the diced Tomatoes and sliced Onions to a medium size bowl.
In a small bowl add the Honey, Dijon Mustard, Lemon Juice, Red Wine Vinegar, Garlic Powder, Salt and Black Pepper. Mix well.
Slowly add the Olive oil to the small bowl whisking to incorporate.
Pour the dressing over the Tomatoes and Onions, toss to coat. Refrigerate until ready to serve.
Add the Basil and stir just prior to serving.