Add the softened butter to a food processor or medium mixing bowl and blend or stir together the butter, garlic, 1 teaspoon of parsley, chives and basil until thoroughly combined.
Evenly spread over both halves of the bread loaf.
Arrange tomatoes in an even single layer over each half of the bread and season with salt and pepper.
Top with the mozzarella and Parmesan cheese.
Bake until the cheese has melted and the edges are golden brown, about 20 minutes.
Cut into slices and serve immediately.
Notes
I like to use a food processor to make the garlic butter. Save yourself some time chopping! Add the butter and garlic, pulsing to combine then add the herbs and pulse until incorporated. You should still be able to see the herbs in the butter mixture.