Use really good bread like a baguette, or a homeade loaf, day old. I use 1/2 of a good bakery baguette, and buy an extra one anytime I know I want salad, trim the end off.
Choose a broad skillet, like a 12-inch sauté pan, it is not good to do them in batches, because the first ones would soak up all the oil.
It does not matter if they overlap.
Put in the oil and all the garlic cloves, and a pinch of salt if desired. Turn the heat to medium and cook until the garlic wilts, and turns gold, crushing it into smaller pieces as it is cooking.
Turn off the heat, set the skillet aside for one good hour ( or as long as you want), then strain, or well-remove the garlic from the oil, and discard, or use for other things.
Cook the croutons over medium heat stirring and tossing very often, seasoning with salt and pepper as nessecary, until golden and delicious.