A comforting and flavorful onion soup enhanced with cider and topped with cheesy croutons.
Melt the butter in a large saucepan over medium heat.
Ensure the butter doesn't brown to maintain a smooth flavor.
Add the onions and sea salt, and cook, stirring occasionally, until the onions are deeply caramelized.
Cook the onions slowly to bring out their natural sweetness.
Pour in the cider and simmer until reduced by half.
Reducing the cider concentrates its flavor.
Add the stock and simmer for 10 minutes. Season with additional salt if needed.
Taste the soup and adjust the seasoning to your preference.
Slice the baguette and place the slices on a baking tray. Grill both sides until lightly toasted.
Ensure the bread is toasted evenly for a perfect crunch.
Spread the toasted bread with mustard and top with grated cheese. Grill until the cheese is bubbly and golden.
Use a mix of cheeses for a more complex flavor.
Serve the soup in bowls, topped with the cheesy croutons and garnished with fresh thyme.
Serve immediately to enjoy the croutons at their best.