Soak the raisins in warm water for 10 minutes to plump them up, then drain well. While they soak, sift the powdered sugar for the glaze to remove any lumps, and measure out your einkorn flour, sugar, salt, spices (cinnamon, nutmeg, cloves, and ginger), and lemon zest into separate small bowls. This mise en place approach keeps the dough-making process smooth and prevents any ingredients from being missed.

Warm the orange juice to about 110°F (just warm to the touch), then combine it with the yeast in a large mixing bowl and let sit for 1-2 minutes to bloom. Add the flour, sugar, salt, all the spices, lemon zest, and drained raisins to the yeast mixture. Stir until everything is roughly combined, then add the butter (cut into small pieces) and the egg. Mix until a shaggy dough forms—einkorn is a delicate flour, so you're not looking for a perfectly smooth dough yet, just all ingredients incorporated.

Knead the dough for 5-10 minutes on a lightly floured surface until it becomes smooth and elastic. I find that einkorn dough is stickier than regular wheat dough, so resist the urge to add extra flour—a slightly tacky dough actually develops better flavor. Transfer the dough to a greased bowl, cover it with a damp towel or plastic wrap, and let it rise at room temperature for 30-90 minutes until it roughly doubles in size. The longer rise time will develop deeper flavor, so don't rush this step if you have time.

Preheat your oven to 350°F and grease a 9x13 inch baking pan or similar size. Turn the risen dough out onto a lightly floured surface and gently divide it into 12 equal pieces (I use a bench scraper to portion evenly). Roll each piece into a smooth ball and arrange them in the prepared pan, spacing them about 1 inch apart so they have room to rise and puff without touching. Cover the pan loosely with a damp towel.

Let the buns rise for 30-45 minutes at room temperature until they're puffy and spring back slowly when poked. Bake them in the preheated 350°F oven for 25-35 minutes until the tops are golden brown and an instant-read thermometer inserted into the center of one bun reads 185°F. Remove from the oven and let the buns cool in the pan for 10-15 minutes before removing them.

While the buns cool, whisk together the sifted powdered sugar, milk, and vanilla in a small bowl until you have a smooth, pourable glaze with a consistency similar to heavy cream. Transfer the cooled buns to a serving platter or wire rack. Using a piping bag, squeeze bottle, or small spoon, drizzle the glaze over each bun in two perpendicular lines to form a traditional cross. Let the glaze set for a few minutes before serving.