Gather all ingredients and ensure eggs are at room temperature—this prevents the butter from seizing when mixed in later. Measure the yeast and ginger into a small bowl. In a separate bowl, combine the warmed water (105-110°F is critical for proper yeast activation), inulin, and sour cream. Pour the liquid mixture over the yeast and ginger, then let it rest undisturbed for 7 minutes until it becomes bubbly and fragrant. This blooming step confirms the yeast is alive and active before committing all other ingredients.

While the yeast blooms, whisk together all dry ingredients in a large bowl: almond flour, flaxseed meal, whey protein, erythritol, xanthan gum, baking powder, salt, cinnamon, nutmeg, and allspice. This ensures even distribution of leavening agents and spices throughout the dough. In the bloomed yeast mixture, whisk in the room-temperature eggs, apple cider vinegar, and orange zest until well combined. I like to add the vinegar as it helps activate the baking powder and brighten the flavor of these buns.

Pour the wet ingredient mixture from Step 2 into the bowl of dry ingredients. Add the softened butter cut into small pieces. Using a wooden spoon or stand mixer, blend everything together for about 1 minute until you reach a smooth, cohesive dough with no dry streaks. The xanthan gum and psyllium husk will give this dough its structure since traditional gluten isn't available. Fold in the chocolate chunks at the end so they're distributed evenly throughout.

Lightly wet your hands with water to prevent sticking, then shape the dough into 8 equal balls. This keto dough is quite sticky, so working quickly and keeping your hands damp is essential. Place the balls on a parchment-lined baking tray, leaving space between them for expansion. Cover loosely with plastic wrap or a damp towel and place in a warm spot (like a turned-off oven with the light on, or near a sunny window) for 1.5 to 3 hours. The dough should roughly double in size and feel airy when gently poked—don't expect the same rise as traditional bread since we're using alternative flours.

About 20 minutes before the buns finish rising, preheat your oven to 375°F. Once the buns are fully risen, brush the tops lightly with egg wash (one beaten egg mixed with a splash of water). Bake at 375°F for exactly 10 minutes to set the structure and create a light crust. Then reduce the oven temperature to 350°F and continue baking for 15-20 minutes more, until the buns are deep golden brown and a skewer inserted into the center comes out clean. The two-stage baking prevents the tops from browning too quickly while the centers finish cooking.

Remove the buns from the oven and let them cool on the baking tray for 20 minutes (this allows carryover cooking and prevents them from being too fragile to move). While they cool, whisk together the powdered erythritol (sifted to remove any lumps for smoothness), vanilla essence, salt, and water in a small bowl until you reach a thick, pipeable paste. The consistency should be similar to thick toothpaste—thick enough to hold its shape when piped but thin enough to flow smoothly from a piping bag.

Once the buns are cool enough to handle, carefully transfer them to a wire cooling rack. Let them cool completely to room temperature, about 10-15 minutes longer. Transfer the icing to a piping bag fitted with a small round tip and pipe a cross on the top of each bun in two intersecting lines. I find that waiting until the buns are completely cool prevents the icing from melting and sliding off. Allow the icing to set for 5 minutes before serving.