Makes 2 Servings
1 large yellow onion , finely chopped (about 1 1/2 cups)
1 tablespoon butter
1 teaspoon Kosher salt
2 tablespoons mayonnaise
1 tablespoon ketchup
2 teaspoons sweet pickle relish, drained
1 teaspoon distilled white vinegar
4 slices deli-cut cheddar cheese
2 lbs russet potatoes, peeled and cut into 1/4 inch fries, submerged in water
1/2 gallon vegetable oil
Fine sea salt
Heat the butter in a medium saucepan over medium-high heat until foaming. Add the onions and the salt. Reduce heat to medium low, and cook, covered stirring occasionally until the onions are translucent and starting to brown, about 15 minutes. Once the onions begin to sizzle and appear dry, add 1 tablespoon water to skillet and stir scraping up any browned bits. Continue cooking uncovered until the water evaporates and onions start sizzling again. Repeat process, adding 1 tablespoon of water with each iteration until onions are meltingly soft and dark brown (about 3 times total). Transfer to a small bowl and set aside.
To make the animal fry spread: Add mayonnaise, ketchup, relish, and vinegar to a small bowl and stir to combine.
Heat the oil to 350° and dry the potatoes. Once the oil is hot, working in batches submerge the potatoes for 3-4 minutes or until the fries start turning a bit whiter (to develop a pale white skin). Remove with slotted spoon onto a rimmed baking sheet lined with paper towel. Continue frying in batches until all of the potatoes have been fried. Turn the heat up to bring the oil to 375°. Put the potatoes back in the hot oil and fry a second time for 2-3 minutes, or until golden brown. Salt to taste and place fries on plate, cover with slices of cheddar cheese (you can put the fries under a broiler to melt the cheese if needed), melted onions, and the animal style spread. Serve immediately.