Preheat the oven:
Set oven to 400ºF (200ºC) and position the rack in the middle.
Marinate the chicken:
In a large bowl, whisk together the Dijon mustard and buttermilk.
Add the chicken and toss to coat evenly.
Prepare the breadcrumb coating:
In a food processor, combine garlic, thyme, lemon zest, salt, and pepper.
Pulse until the garlic is finely minced.
Add the breadcrumbs and olive oil, pulsing a few times to moisten the mixture.
Transfer to a shallow bowl or large plate.
Coat the chicken:
Line a baking sheet with parchment paper.
Dip each piece of chicken skin-side down into the breadcrumb mixture, pressing gently to adhere.
Place the chicken crumb-side up on the baking sheet.
If needed, press extra breadcrumbs onto the chicken for an even coating.
Bake the chicken:
Bake for 40 minutes, then check for doneness.
If needed, bake for an additional 5 minutes until golden brown.
Let rest 5-10 minutes before serving.
Serve and enjoy!
This dish can be served hot, warm, or at room temperature.