Ingredients
Equipment
Method
Caramelize the onions
- Heat butter and olive oil in a Dutch oven over medium heat, then add onions and stir to coat. Cook until deeply caramelized for 40 minutes, stirring as needed to prevent scorching, until the onions are dark golden-brown.
- Stir in sugar and cook 1 minute more, then add Worcestershire sauce and stir to combine. Cook for 1 additional minute so the onions absorb the flavor, then turn off the heat.
Make the cheesy onion filling
- Transfer onions to a bowl and cool until warm rather than hot. This helps prevent the cream cheese from melting too runny.
- Mix cooled onions with shredded gruyere, softened cream cheese, and fresh thyme. Stir until the mixture is thick and cohesive for easy stuffing.
Stuff and sear the chicken
- Cut a pocket into each chicken breast, keeping the sides intact as you slice. Season the inside and outside with salt and pepper.
- Stuff each pocket generously with the onion-cheese mixture, then secure with toothpicks. Press lightly so the filling sits inside without spilling out.
- Heat a clear spot in the pan (or return to heat in the Dutch oven) and sear chicken for 3 minutes per side. Cook until golden brown with visible browning on both faces.
Bake, rest, and serve
- Bake on a sheet pan at 375F for 20-25 minutes, until chicken is cooked through. Rest for 5 minutes after baking so the juices redistribute, then remove toothpicks and serve.
Notes
Pro tip: give the onions a full 40 minutes—rushing the caramelization is the main reason the filling tastes flat. Store leftovers in the fridge up to 3 days in an airtight container; reheat gently to keep the chicken juicy. Freezing: freeze cooked chicken up to 2 months, then thaw in the fridge and reheat at 325F until hot. For a lower-fat swap, use reduced-fat cream cheese and use part-skim gruyere.