Steam the cauliflower florets until very tender, then mash with a pinch of sea salt until smooth and creamy.
Season the chicken breast evenly on both sides with sea salt and garlic powder.
Heat the ghee in a large stainless steel or cast iron skillet over medium-high heat.
Place the chicken in the skillet and sear for 6 to 7 minutes per side until golden brown and the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest on a plate.
Add the asparagus spears to the same skillet and sauté for 3 to 4 minutes until bright green and crisp-tender, then remove and set aside.
Pour the beef broth into the hot skillet, using a wooden spoon to scrape up all the browned bits from the bottom of the pan.
Stir in the crushed black peppercorns, Dijon mustard, and heavy cream, whisking constantly.
Simmer the sauce for 2 to 3 minutes until it reduces slightly and becomes glossy and thick.
Slice the chicken breast and serve it over the cauliflower mash, drizzled generously with the peppercorn sauce and accompanied by the sautéed asparagus.