Add the olive oil to a large pot over medium-high heat. When the oil is hot add in the diced onion and sauté 2-3 minutes. Add in 1 tablespoon of the fresh chopped dill, lemon zest and the chicken broth. Season with salt and pepper and bring to a boil.

Add in the cauliflower rice and simmer until it's tender, about 6-8 minutes.

In a small bowl whisk the arrowroot powder (or cornstarch) and lemon juice together until the arrowroot is dissolved.

Whisk the eggs into the lemon juice mixture then slowly ladle in about 1-2 cups of the broth whisking the entire time so that the eggs don't curdle. Once the mixture comes to temperature whisk it back into the soup pot. Continue to stir the mixture until it thickens slightly, about 5 minutes.

Add in the shredded chicken and remaining tablespoon of chopped dill. Taste for seasoning and adjust as needed. Serve the soup topped with thin lemon slices and extra dill if desired.