Preheat oven to 400 degrees F (200 degrees C).
Fill a medium bowl with cold water. Peel the Russet Potato (2). Cut them lengthwise into quarter inch slices or planks. Stack several potato planks on top of each other and then cut them lengthwise again into quarter inch slices. Place into the bowl of water to release starch.
Slice Tomato (1) into quarter-inch slices. Set aside.
Drain the potatoes into a colander and dry out the bowl with paper towels. Pat dry the potatoes and then place back into the bowl. Drizzle with Olive Oil (2 tablespoon) and season with Salt (1/4 teaspoon) and Ground Black Pepper (1/4 teaspoon). Toss to coat well.
Cover a sheet pan with foil. Lightly coat the foil with non stick spray. Place the potatoes in a single layer onto the sheet pan and bake for thirty minutes.
Meanwhile, lay the tomato slices onto another sheet pan and evenly drizzle with Olive Oil (1 tablespoon) and Balsamic Vinegar (2 teaspoon). Season with Salt (1/4 teaspoon).
Place tomatoes in the oven, and roast for fifteen minutes. When putting the tomatoes in the oven, rotate the pan with the potatoes.
While the potatoes and tomatoes are roasting, heat a large saute pan over medium-high heat. When hot, add Olive Oil (1/2 teaspoon) and the Pancetta (6 ounce). Season with Ground Black Pepper (1/4 teaspoon) and cook until crisp, about two minutes per side.
Remove pancetta from pan and place onto paper towels. Set aside.
Heat one tablespoon of Unsalted Butter (2 tablespoon) in a large saute pan over medium heat. Add two pieces of Sourdough Bread (4 slice) and cook until toasted on one side only, about one minute.
Remove bread from saute pan and repeat the process with the other slices of bread and butter.
In a small bowl, stir the Mayonnaise (2 tablespoon) with Malt Vinegar (1/2 tablespoon) and Sour Cream (2 tablespoon). Spread the mayonnaise mixture evenly onto the untoasted sides of bread.
Take 2 leaves from the Escarole Lettuce (1) and top each one with a leaf, several tomato slices, and an equal amount of pancetta. Place the remaining slices with the mayonnaise mixture on top.
Slice each sandwich in half to make triangles. Place two sandwich halves on each of two plates. Divide french fries evenly with ketchup on the side. Serve the remaining mayonnaise mixture on the side as a tasty dip for the potatoes!