4 1/2 pounds Roma tomatoes chopped
1 1/2 tablespoons kosher salt
4 sheets of gelatin or 1 envelope of Knox unflavored gelatin
1 teaspoon sugar
1 tablespoon champagne vinegar
10 medium heirloom tomatoes such as red Brandywine
1 1/2 pounds of fresh mozzarella
20 - 25 large basil leaves
Sprinkle kosher salt over chopped Roma tomatoes and toss. Wrap tomatoes in cheese cloth and tie with a heavy duty string. Hang over night over a bowl to collect tomato juice; you will need one cup of tomato juice. Reserve tomato pulp for another use.
Stir gelatin powder directly into the tomato juice and let it sit for 5 minutes. If using gelatin sheets, soften in 2 cups of cold water for 5 minutes. Remove sheets from cold water and stir into 1 cup of tomato water.
Heat tomato juice over low heat to dissolve gelatin. Add the sugar and vinegar. Simmer for about 2 minutes to blend the flavors and cool.
Chill the fresh mozzarella in the freezer for about 10 minutes to firm up the cheese for ease in slicing. Slice heirloom tomatoes into quarters and cut thin slices lengthwise. Thinly slice the chilled cheese. Remove excess moisture from tomatoes and cheese by patting the slices with paper toweling.
Line a terrine or mold (9 1/4 by 4 by 2 3/4 inches) with plastic wrap. Spread just enough of the tomato gelatin to cover the bottom of the mold, about 2 tablespoons. Neatly lay thinly sliced tomatoes along the bottom of the mold, again spread a thin layer of tomato gelatin over the sliced tomatoes. Continue the next layer with the sliced mozzarella, top with another thin layer of tomato gelatin. Follow with a layer of basil leaves. If basil leaves do not lay flat gently slice leaves half way down the middle so the leaf can lay flat. Top with another layer of tomato gelatin. Continue the above pattern until the top of the mold is reached. Cover with plastic wrap and refrigerate for at least 3 hours or overnight.
To serve: remove plastic wrap and invert terrine on a plate. Cut into 1/2" slices and drizzle basil oil and balsamic glaze around slices and serve.