Cut potatoes with a mandoline or the slicer side of a grater.

Heat oil in a 6- or 8-quart pot over high heat. There should be enough oil to cover the chips while they’re frying.

When oil is hot, add the chips in batches. Use a wooden spoon to separate any chips that are sticking together. Fry for 4–5 minutes without mixing.

Remove chips from oil using a slotted spoon, and transfer to a paper towel-lined plate. Season with salt and pepper.

Fill a spray bottle with vinegar and spray the chips (optional). Serve with homemade ketchup.

Heat oil in a medium saucepan. Add garlic, tomatoes, spices, brown sugar, and vinegar, and stir for 1 minute. Add tomato paste.

Scrape up any browned bits from the bottom of the pot with a wooden spoon and remove from heat.

Purée ketchup in blender or using an immersion blender, until smooth. Bring to a simmer over medium-low heat and cook, stirring occasionally until thick. Transfer to airtight container.