Combine water, kosher salt, and honey in a large pot. Simmer for 2 minutes, stirring until dissolved.
Add bay leaves, garlic, peppercorns, lemon slices, and herbs. Bring to a brief boil, then remove from heat.
Cool completely before adding chicken.
Submerge the chicken in the cooled brine. Cover and refrigerate for 8–24 hours.
When ready, remove chicken and rinse under cold water. Pat dry.
Discard the used brine.
Mix softened butter, garlic, herbs, lemon zest, Dijon mustard, salt, and pepper in a bowl until smooth.
Rub chicken all over with olive oil, salt, and pepper (inside and out).
Stuff the cavity with lemon halves, onion quarters, and a few sprigs of rosemary and thyme.
Gently loosen the skin over the breast and thighs.
Spread garlic herb butter evenly under the skin and over the top of the chicken.
Preheat oven to 425°F (220°C).
Place chicken breast-side up on a rack in a roasting pan. Add broth to the pan if desired.
Roast 1–1¼ hours, or until internal temperature reaches 165°F (75°C).
If browning too quickly, tent loosely with foil.
Let the chicken rest for 15 minutes before carving.
Spoon pan juices over slices for extra flavor. Serve warm.