At Bichettes in Paris, chef Hortense Thireau prepares a French onion soup that is brighter and more herbaceous than typical versions. She caramelizes the onions less aggressively, deglazes only once with white wine, and swaps chicken stock for the typical beef stock—all tricks to keep things light. Additionally, rather than top her soup with bread, which becomes heavy as it soaks up broth, Thireau seals each bowl with a puff pastry lid. In the oven, the cheese-topped pastry crisps as it turns golden brown. Crock-like oven-safe bowls, each with a 12-ounce capacity, are best, but it’s possible to make this recipe without ovenproof bowls. In that case, while the onions caramelize, bake the egg-washed, cheese-sprinkled pastry rounds on a parchment-lined baking sheet for 25 to 30 minutes. Once the soup is portioned, simply top each bowl with a baked pastry round, or serve them alongside for dipping. Dufour frozen puff pastry is the hands-down best choice for this. Pure butter gives it a rich, sweet flavor, and it bakes up with a satisfying, almost bready texture. If Pepperidge Farm frozen puff pastry is the only option, you’ll need just one sheet from a 17.3-ounce box. After thawing and unfolding, if the sheet is too small to yield four rounds that are slightly wider than the bowls, give it a few passes under a rolling pin so it’s just large enough (Dufour pastry will not need to be rolled out unless your bowls are very wide). Comté is a nutty, buttery cow’s milk cheese; Gruyère is an excellent substitute.