Prepare a ceramic ramekin by rubbing cold butter all over the inside until a thick layer is visible. Set the buttered ramekin in your refrigerator to chill. You must use a ceramic ramekin for this recipe. This style of baking dish is safe to heat in your oven and is in a particular shape/style for souffles. Turn on your oven to preheat to 350 degrees.
Divide an egg into a white and yolk. Set the yolk aside somewhere safe while you whip the egg white and cream of tartar in a stand mixer with a whip attachment. You may also do this in a bowl with a hand mixer. Whip the egg white until you have stiff peaks. Transfer the whipped egg white to a small bowl and set aside.
Wipe your mixing bowl clean quickly and place in the egg yolk. Whip the egg yolk until it turns pale yellow. Then, whip in the cream. On a slow speed, whip into the egg yolk the paleo flour, salt, old bay, pepper, mustard powder, and xanthan gum. Use a spatula to fold in by hand crab meat that has been well-drained. Follow by folding the cheese and chopped green onion into the batter as well.
Finally, fold the egg white into the souffle batter in 2-3 additions. Fold the egg white in half way before adding in more. Fold the batter together after the final addition of egg white has been added. Pour the souffle batter into your cold, buttered ramekin. Rub your thumb along the inner rim to create a small lip in the batter, as pictured.
Set the filled ramekin on a sheet tray and place it in your oven. Bake the souffle for 20-25 minutes, until you can tap the top without it sinking in and the top of the souffle turns lightly golden. Serve the souffle right away while it’s hot, being careful not to burn your hands on the ceramic ramekin. Enjoy with your breakfast or as a satisfying snack.