1. Heat olive oil in a large skillet over medium-high heat.

2. Add the diced onion, cooking until it starts to soften, about 5 minutes.

3. Add the ground chicken and cook until browned, breaking it up into chunks as you go.

4. Once the chicken is cooked, add the shredded zucchini and Italian seasoning and cook until the zucchini softens, another 3 to 4 minutes.

5. Add the marinara and cook for another 5 minutes.

6. Finally, add the mozzarella, turn the heat to low and cover until the cheese is melted, about 4 to 5 minutes. Alternately, if you are making this in an oven-proof skillet, you can broil the cheese to melt it.

7. Top with golden buttered breadcrumbs and serve on toasted brioche buns

To make the buttered breadcrumbs:

1. You can make the breadcrumbs while the chicken mixture is cooking.

2. Heat the butter over medium heat.

3. Add the breadcrumbs and stir to mix with the melted butter.

4. Cook for 2 to 3 minutes until the breadcrumbs are slightly golden.