Trim the ends off of the celeriac bulb and peel. Using a sharp chef's knife, chop the bulb into small cubes.
In a small saucepot, bring the celeriac cubes and broth to a boil. Boil for 8 minutes, then drain thoroughly and set aside.
Heat the avocado oil in an enameled cast-iron skillet over medium-high heat. Pat the celeriac dry and add it to the skillet. While it fries, chop your onion and pepper, then add it to the skillet and stir it in with the salt and pepper. Continue stirring occasionally as you finish the rest of the recipe.
Heat a non-stick skillet over medium to medium-high heat, and cook your breakfast sausages until they're thoroughly browned. Remove them from the pan, cut each one into four pieces, then stir them into the skillet with the celery root.
Turn the non-stick skillet down to medium, then melt the butter in it. Beat the eggs, then scramble them in the butter. When they're finished, stir them into the celery root mixture, add more salt and pepper if needed, and serve.
Macros per serving: 409 calories, 7 grams net carbs, 18 grams protein, 33 grams fat.