Step 1: Make dough
In a large bowl, combinewarm water, Murray River Salt Flakes, sugar, and yeast. Let sit for about 5 min., or until mixture begins to foam slightly. Add 4 cups flour and melted butter and mix with your hands until dough begins to come together. Add more flour in 1/4 cup increments if dough is sticky and wet. Knead for 4 to 5 min. or until dough forms a smooth ball and does not break when stretched. Drizzle olive oil in the bowl and turn dough over to coat. Lightly cover bowl with a towel or plastic wrap and let dough rise for about 1 hour or until it has doubled in size.
Step 2: Form pretzels
Preheat oven to 450 degrees. Line 2 sheet pans with parchment paper and set aside. In a large pot, bring 10 cups water and baking soda to a rolling boil. Turn dough out onto a lightly oiled surface and divide into 8 equal pieces. Roll out each piece into a 24-inch long rope. Make a U-shape with the rope and cross the ends over each other and press into the bottom of the U in order to form the shape of the pretzel. Place each pretzel gently onto a parchment-lined sheet pan.
Step 3: Boil and bake
One by one, gently place each pretzel into the boiling water for 30 seconds, and lift out using a large slotted spoon or spatula. Return boiled pretzels to the sheet pan, brush the top with beaten egg, and sprinkle generously with Murray River Salt Flakes and Crushed Allepo Chiles. Bake until golden brown, about 12 to 15 min. Transfer to a rack and let cool for at least 5 min. before serving.