Special equipment: a mandoline
Make 4 parchment paper cones and place them in 4 cups.
Heat the oil, along with the thyme, garlic, rosemary and sage, in a heavy-bottomed pot over medium heat to 365 degrees F. The herbs should be nice and crackly at this stage. Using a slotted spoon, transfer the herbs and garlic to a paper towel-lined plate. Set aside.
Using a mandoline, cut the potatoes into matchsticks and place in a large bowl of ice water. Soak for a few minutes, then rinse with cold water until the water runs clear. Drain the matchsticks and pat dry in a kitchen towel to remove as much water as possible. Fry in small batches until golden and crispy, 2 to 3 minutes. Transfer to the paper cones and season with some Cajun Spice Mix. Peel the fried garlic cloves and sprinkle them and the fried herbs over the potatoes.
Mix together the garlic powder, onion powder, smoked paprika, cayenne, salt and pepper in a small bowl.