Wash and dry the potatoes. Place them in a large pot and cover with water.
Let the potatoes come to a boil, and then turn down to a simmer. Cook for 6-7 more minutes or until an inserted fork can easily pierce it, but the potato doesn't fall apart. Remove from heat and drain the water. Set potatoes aside.
Preheat the oven to 350 F.
Spray the potatoes with avocado oil (or toss in olive oil), salt, and pepper.
Put the potatoes in an oven safe baking dish, and then toss the tomatoes in the remaining oil. Add them to the potatoes in the baking dish.
Bake for 25 minutes, or until potatoes are tender and easily pierced with a fork.
Remove the baking dish, and place half the package (4-5 slices) of cheese atop the potatoes and tomatoes.
Put back in the oven for 5 more minutes.
To serve, scoop potatoes and tomatoes with melted raclette on a plate. Add cornichons to the side, and eat once the food has cooled enough to be edible.