Preheat the oven to 400˚ F. Spread the walnuts on a baking sheet and bake until golden brown, about 5 minutes. Let cool completely.
Pulse 1 cup walnuts, the garlic and 1/4 cup olive oil in a food processor to make a paste, about 1 minute, scraping the bowl as needed. Add the remaining 1 cup walnuts and 1/4 cup plus 2 tablespoons olive oil, the vinegar and a pinch of salt. Pulse until combined but still chunky.
Transfer to a bowl and stir in the parsley and thyme; season with salt.