In the bowl of a standing mixer, stir together active sourdough starter, water, sugar and salt with a spatula. Add the bread flour and stir together. The dough will be shaggy. Place the dough hook on the mixer and mix on the lowest speed for 5 minutes.
Place dough in a bowl, cover with plastic wrap and place in the fridge for 16-24 hours. (Alternatively, you can allow the dough to rise on the counter for 8-12 hours)
Remove the bowl from the fridge and allow to rest at room temperature for a couple hours.
Line a baking sheet with parchment paper. Place dough on a clean work surface and divide into 8 equal pieces. A scale will be helpful here.
Roll each piece into a long rope and then shape into a pretzel. Place on the prepared baking sheet, cover with a clean towel or plastic wrap and rest for 30 minutes – 1 hour.
Meanwhile, preheat oven to 425 F. Add water to a medium sized pot and bring to a boil. Once boiling, add baking soda and brown sugar, stirring to combine.
Boil the pretzels, 3 at a time, for 30 seconds each. Use a mesh strainer to remove the pretzels and place them on a cooling rack. After the pretzels have dried slightly, place them on the baking sheet with parchment paper.
Brush each pretzel with olive oil and sprinkle course salt over the top.