In a large bowl, dissolve the brown sugar in 2 cups of warm water. Sprinkle the yeast over the top and let sit for about 5 minutes until foamy.

Stir in the vegetable oil, kosher salt, and 3 cups of flour. Gradually add the remaining 2 ¾ cups of flour and knead until a slightly sticky dough forms.

Transfer the dough to a floured surface and knead for about 3 minutes until smooth and elastic. If too sticky, add up to ¼ cup more flour.

Place the dough in a greased bowl, cover with plastic wrap, and let it rise at room temperature for about 45 minutes or until doubled in size.

Preheat the oven to 450°F and adjust the rack to the center position. Grease four large baking sheets, line them with parchment paper, and grease the paper.

Punch down the dough, transfer it to a floured surface, and divide it into 24 equal pieces.

Roll each piece into a 9-inch rope, about ½-inch thick. Arrange them on the prepared baking sheets, spacing them 2 inches apart. Let them rest, uncovered, for about 25 minutes until slightly puffed.

In a large, deep skillet, combine 2 quarts of water with the baking soda and bring to a simmer over high heat. Reduce the heat to medium.

Using spatulas, carefully lower six pretzel sticks at a time into the simmering water for 30 seconds, turning once.

Transfer the boiled pretzel sticks to a wire rack-lined baking sheet to drain, then return them to the parchment-lined baking sheets, spacing them evenly.

Brush each pretzel stick with the egg wash and sprinkle with flaky salt.

Bake one sheet at a time on the center rack for 8–10 minutes, or until golden brown.

Enjoy warm or at room temperature with mustard.