Make the dough: In a medium bowl, add the flour and yeast; whisk to combine. Set aside. (Note: if using a baking soda bath in place of a lye bath, refer to the notes below to create the bath as step 1 – then proceed to make the dough.)
In the bowl of a stand mixer fitted with a dough hook, add the water, barley malt syrup and salt. Add the flour-yeast mixture and mix on low speed (speed 1) until the dough just comes together, about 1 minute. While mixer is still going, add the butter pieces; mix until the butter is completely incorporated. Increase mixer speed to medium (speed 4-5) and continue mixing for 10-15 minutes or until the dough is shiny, smooth and elastic.
Bulk rise: Spray a large bowl with non-stick cooking spray and transfer the dough to the bowl. Spray the top of the dough with non-stick spray; cover bowl with plastic wrap and set in a warm place. Allow dough to bulk ferment for 20-30 minutes. To make shaping easier, after the rise, place dough in the refrigerator for up to 30 minutes to firm it up. Divide dough: Turn dough out onto a clean work surface. Press dough gently with fingertips to degas. Divide the dough into 12 equal portions (about 84 grams each). Gently roll each piece into a cigar-shaped log, about 8-9 inches long; cover dough with plastic wrap. Let the pieces rest for 10 minutes.
Prepare baking pans: Line two ½-sheet pans with a silicone baking mat or parchment. Coat with non-stick cooking spray. Set aside.
Shape the pretzels: With the palms of your hands, roll and stretch each piece into a 24 to 26-inch rope of even thickness throughout. Form the dough into a U shape; crisscross the ends twice, leaving the remaining ends 3 inches long. Bring the ends to the lower sides of the U shape and press ends to secure. Stretch the pretzel to even out its shape. (View step-by-step pictures in the Bavarian pretzel tutorial). Place shaped pretzel on the prepared sheet pan; cover with plastic wrap. Continue shaping the remaining dough.
Place covered dough into the freezer to stiffen the pretzels, about 5-10 minutes. (Note, this may take a bit longer if your freezer is very full or not as cold; you want the dough to be slightly firm but NOT frozen.)
Preheat oven to 425˚F.
Prepare the lye bath: Please note, safety is of utmost importance when using lye. Please follow the instructions carefully. We recommend watching the video tutorial for more tips on using the lye bath before proceeding. (Instructions for using an alternate baking soda and egg wash method in place of a lye bath can be found in the notes below this recipe.)Cover your work station in parchment paper. Wear eye protection and rubber or latex gloves. Wear long sleeves to cover arms.Add cold water in a non-reactive bowl (stainless steel works best) and then slowly add the lye; stir to dissolve. The chemical reaction will warm the mixture, so allow to cool before dipping the pretzels, about 5 minutes. Soak the pretzels in the lye bath: Transfer the stiffened pretzels to the bath, one at a time, and let soak for 5 seconds on each side (no more than 10 seconds total). Place the pretzels on a stainless steel cooling rack that is resting on a parchment-lined baking sheet to catch any excess solution. Carefully dispose of the lye bath by slowly pouring solution down the drain of your kitchen sink.
Toppings: Transfer the pretzels back to the prepared sheet pans. Sprinkle salt over top of pretzels, as desired.
Bake: Bake for 16-20 minutes, until deep, golden brown.