Preheat oven to 425F. Line a baking sheet with parchment or silicone liner.
Pulse pecans in a food processor until the consistency of coarse sand. Combine with salt and pepper in a shallow bowl.
Gently whip egg white with a fork.
Dry chicken breasts with paper towel. Dredge in egg white and gently wipe off excess with your fingers. Dredge in pecans then place on prepared baking sheet.
Bake for 25 minutes, flipping at the 15-minute mark.
Meanwhile, cut cauliflower into florets. Place in a pot with garlic and broth.
Bring to a boil, then reduce heat to maintain a simmer. Simmer 15 minutes, until cauliflower is overcooked. Pour broth and cauliflower into a high powered blender. Blend for 1 minute, or until completely smooth. Taste and season with salt to taste.
Serve chicken with gravy.