Begin by slicing the beefsteak tomatoes into ⅓-inch thick slices, ensuring you have a mix of vibrant red and yellow hues for visual appeal. Arrange the tomato slices in an even layer in a shallow dish.

In a separate bowl, whisk together ¼ cup of olive oil, 2 tablespoons of red wine vinegar, and 2 tablespoons of lemon juice. Next, add ¼ cup of minced red onion, ¼ cup of diced fresh basil, and ¼ cup of chopped fresh parsley. Finally, incorporate 2 cloves of crushed garlic, a pinch of fine sea salt, and some fresh ground pepper, mixing until well combined.

Carefully pour the flavorful marinade over the arranged tomato slices, ensuring each piece is thoroughly coated. Gently toss the tomatoes with the marinade using a spatula or tongs to promote even coverage.

Cover the shallow dish with plastic wrap or a lid, then place it in the refrigerator. Allow the Italian Tomato Salad to marinate for at least 1 hour, or up to 8 hours.

Once marinated, remove the salad from the refrigerator and give it a gentle toss. Serve chilled.