01 - In a mixing bowl, combine flour, yeast, and salt. Gradually add warm water and mix until a dough forms. Knead for about 5 minutes until smooth.
02 - Cover the dough and let it rise in a warm place for 20 minutes.
03 - While the dough is rising, melt butter in a skillet over medium heat. Add the sliced onions and sauté until softened, about 5 minutes. Pour in the beer and cook until the onions are caramelized and the liquid has reduced, about 15 minutes. Season with salt and pepper.
04 - Preheat the oven to 425°F (220°C).
05 - Bring a pot of water to a boil and add the baking soda.
06 - Divide the dough into 12 equal pieces and shape each into a small bun. Boil the buns in the soda water for 30 seconds on each side, then place them on a baking sheet lined with parchment paper.
07 - Bake for 15-20 minutes, or until golden brown.
08 - For the mustard cream, mix the sour cream, Dijon mustard, and honey in a small bowl.
09 - Serve the pretzel buns topped with beer-caramelized onions and a drizzle of mustard cream.