In a large bowl, combine the warm water, light brown sugar, and instant yeast. Let stand until foamy, 5β10 minutes.
Add the all-purpose flour and kosher salt to the bowl, then pour in the 2 tbsp melted and cooled unsalted butter. Mix until a shaggy dough forms, then knead on a lightly floured surface (or with a mixer) until smooth, elastic, and slightly tacky, 5β7 minutes.
Grease a large clean bowl with the vegetable oil. Place the dough inside, cover, and let rise in a warm spot until doubled in size, 45β60 minutes.
Preheat the oven to 450Β°F. Line two baking sheets with parchment. In a wide pot, bring the 10 cups water to a gentle simmer, then carefully stir in the baking soda until dissolved. Keep at a bare simmer.
Turn the risen dough out and divide into 8 equal pieces. Roll each piece into a 24-inch rope. Form a U, cross the ends twice, then fold the twisted ends down to the base to make a classic pretzel shape, pressing to adhere.
Using a slotted spatula, lower 1β2 pretzels at a time into the simmering baking soda bath for 20β30 seconds, until slightly puffed. Lift, drain well, and arrange on the prepared sheets, spacing apart.
Bake until deep golden brown, 10β12 minutes. Rotate pans once for even color if needed.
While pretzels bake, mix the granulated sugar and ground cinnamon in a wide shallow bowl.
While hot, brush pretzels all over with the 4 tbsp melted unsalted butter, then toss each pretzel in the cinnamon sugar to coat evenly. Serve warm.