To make the vinaigrette, in a bowl, combine the olive oil and vinegar and gently whisk or mix with a fork. Add the salt and pepper. Taste and adjust the seasonings. Set aside.
Shape the cheese into 4 equal rounds, each 3 inches in diameter and 1/2 inch thick. If using a log-shaped cheese, cut it into 4 equal slices, each 3/4 inch thick.
In a bowl, stir together the bread crumbs, salt, pepper and thyme. Spread the mixture on a piece of waxed paper. Working with 1 round of cheese at a time, press both sides into the mixture to coat it. Set aside.
In a large bowl, combine the arugula and the vinaigrette and toss to coat. Divide the salad among individual salad plates. Set aside.
In a small fry pan over medium heat, warm the olive oil. Add the cheese rounds and cook until lightly golden, 1 to 2 minutes. Turn the rounds over and cook until the cheese begins to melt and spread slightly, about 1 minute more. Remove the pan from the heat. Using a spatula, quickly transfer each browned cheese round to a salad, gently sliding it on top. Serve immediately.
Adapted from Williams-Sonoma Essentials of French Cooking, by Georgeanne Brennan & Sarah Putnam Clegg (Oxmoor House, 2009).