Activate the yeast: In a small bowl, whisk together warm water and sugar. Sprinkle yeast on top and wait 5–8 minutes until foamy.
Mix dry ingredients: In a large bowl or stand mixer, whisk flour blend, tapioca starch, xanthan gum (if needed), and salt.
Combine wet and dry: Add oil and vinegar to the yeast mixture, then pour into dry ingredients. Mix on low (or by hand) until combined, adjusting with extra water as needed to form a tacky, slightly sticky dough.
Rest the dough: Cover the bowl with plastic wrap or a damp towel and let it rest for 20–30 minutes.
Shape pretzel bites: Divide dough into 3–4 portions. On a lightly dusted surface (with tapioca starch or GF flour), roll each portion into ropes about 1 inch thick. Cut ropes into 1–1.5 inch bite-sized pieces.
Prepare the baking soda bath: Preheat your oven to 425°F (220°C). Bring 2 liters of water to a gentle boil in a wide saucepan, then carefully stir in baking soda (water will bubble). Reduce to simmer.
Boil the bites: Working in batches, use a slotted spoon to drop 12–15 pretzel bites at a time into the simmering soda bath. Simmer 12–20 seconds, turning once. Then remove and drain briefly.
Transfer & finish: Place boiled bites on a parchment-lined baking sheet, spaced about 1 inch apart. Brush each with the beaten egg (or plant milk) and sprinkle with coarse salt or your topping of choice.
Bake: Bake in the preheated oven for 12–16 minutes, rotating the tray halfway through. For deeper browning, optionally broil for 1–2 minutes at the end, watching carefully.
Cool & serve: Transfer to a cooling rack for 5–10 minutes. Serve warm with your favourite dip.