Step 1Heat the oven to 325 degrees. Grease a baking sheet and set it aside.
Step 2Spread the almonds on a dry baking sheet and toast the nuts until lightly browned, 5 to 6 minutes. Cool, then finely grind in a food processor.
Step 3Place the blueberries and almonds in a small bowl and add 1/2 tablespoon of flour and stir to coat. Set aside.
Step 4Stir the yeast into the warm water to dissolve. Let it stand for 5 minutes.
Step 5Scald the milk in a small saucepan on low heat or by heating it in the microwave 2 minutes. Place the scalded milk in the bowl of an electric mixer and add the butter, salt and sugar. Stir until the sugar dissolves and the butter has melted. Let the mixture cool to room temperature, then stir in the yeast.
Step 6Add the egg and beat until smooth. Add 2 cups of flour, the ground cardamom, the nuts and blueberries and slowly mix in. Add 2 more cups of flour and mix on medium speed until you have a soft dough, about 1 minute.
Step 7Scrape the dough out onto a floured work surface. Knead for 5 to 7 minutes, adding up to 1/2 cup additional flour as needed until the dough is no longer sticky but smooth. To knead in the electric mixer, replace the paddle with the dough hook and knead on medium speed until you get a smooth dough, about 5 to 6 minutes.
Step 8Place the dough in a large greased bowl, cover and place the bowl in a warm place until the dough has doubled, about 1 to 1 1/2 hours.
Step 9When the dough has doubled, place it on a floured surface, punch it down and divide it into 3 equal pieces. Roll out each piece into a 12-to 14-inch rope with the ends slightly tapered. Place the 3 strips side by side and pinch the top ends together to seal, then tuck the ends under. Lift the left strand and place it between the center and right strands. Then lift the right strand and place between the other 2, keeping the strands evenly spaced. Continue braiding in this way to the end, then seal the bottom pieces by pressing together, then tuck under.
Step 10Place the braided loaf on the greased baking sheet and brush the loaf with the beaten egg. Sprinkle with crystal sugar and let rest for 10 minutes. Meanwhile, heat the oven to 375 degrees.
Step 11Bake the bread until it is deep golden and sounds hollow when thumped on the bottom, 30 to 35 minutes. If it starts to brown too quickly, cover loosely with foil. Remove the foil for the last few minutes of baking.
Step 12Let the loaf cool completely before slicing. It will keep at room temperature in an air-tight container for up to 3 days, or may be frozen.