Starting from cold, fry the garlic in oil (enough to eventually cover the nuts) in a small pan over medium-low heat. When garlic turns golden brown, remove with a slotted spoon and drain on paper.
Add walnuts to the oil and fry until they are as dark as you can get them without burning, keep in mind that they will continue to brown as they cool.
Crush the crispy garlic and thyme leaves in a mortar and pestle until fine, then add the walnuts and pound, but leave a little texture. Add the olive oil and stir in crunchy salt to taste, also seasoning with pepper.
Add plenty of salt to give the sauce a lift, can be refrigerated for a long time but serve at room temperature.
Serve sparsely drizzled over al dente pasta topped with shavings of parmesan.