01 -
Preheat oven to 200°C for toasting the buns later.
02 -
Heat a large sauté pan over medium-high. Add ground chicken, breaking it up as it cooks. Sauté until chicken loses all pinkness and begins to brown at the edges, about 5–7 minutes.
03 -
Add diced yellow onion to the chicken and cook, stirring, until onions soften and turn translucent, approximately 3–4 minutes.
04 -
Pour in marinara sauce, basil pesto, salt, and black pepper. Stir until mixture is evenly combined, then bring to a gentle simmer.
05 -
Reduce heat to low. Sprinkle shredded Parmesan into the mixture and stir until cheese melts. Let simmer gently while preparing buns, allowing flavors to meld.
06 -
Arrange split brioche buns cut-side up on a baking tray. Spread softened garlic butter on both halves. Toast in preheated oven for about 5 minutes, until lightly golden around the edges.
07 -
Set bottom halves of buns on serving plates. Spoon the hot chicken mixture evenly among the buns.
08 -
Top chicken mixture with shredded mozzarella. If a more melted cheese topping is desired, briefly return the bottoms to the oven for 1–2 minutes.
09 -
Cap each sandwich with its bun top, garnish with fresh basil if desired, and serve immediately while hot.