Set the oven to 350 degrees Fahrenheit.
Butter two sizable baking trays. While the oven is preheating, put one pan inside.
Salt, baking soda, and sugar are all combined in a medium dish. Add the flour and stir well to incorporate.
Whisk egg yolks. Add half the remaining dry ingredients. Mix melted butter with electric beaters. Add the remaining dry ingredients slowly to mix.
Onto the hot, greased pans, lay the second layer of dough. Divide the dough into four equal parts. Make 12-inch logs.
To guarantee a clean cut, score the top into rectangles and then trim off any extra dough. Do not omit this process or the tops will turn out tough and rubbery when cooked. Sprinkle the tops with the reserved flour.
For about 20 minutes, or until firm but not browned, bake the biscuits. Take out of the oven, then let cool on the trays. Continue by using the leftover butter.
Prepare to slice after the food has chilled. Lay each dough piece on its side on a cutting block after carefully picking it up by its scored ends. Run the other end of the wood over the straight edge while holding one end firmly against it with a knife or other straight edge.
Create cookies: Divide each piece in half to create two flat biscotti halves, then gently dust with flour. About 15 inches long and 3 to 4 inches broad, roll into cylinders. Six strips should be cut from each cylinder; roll the strips between your hands to reshape them.
To help hold the segments together, several times wrap each strip around itself. Place on baking pans covered with parchment paper. Put some more flour on top. Until browned, bake for 10 to 12 minutes. Place on wire racks to fully cool. Serve immediately or keep for up to seven days in airtight receptacles.