1. Start by placing your starter, water, honey, cinnamon and 2 cups of flour to the bowl of your stand mixer.
2. With the dough hook attachment, knead the bagel dough on low speed for about 10 minutes. 
3. Add the remaining flour gradually and continue to knead until fully incorporated. Add blueberries.
4. Cover the dough with a plastic wrap or damp tea towel and leave in a warm place to ferment for 8-12 hours. 
5. After the dough has fermented, divide it into 8 equal pieces. 
6. Roll into dough balls, flatten with your palm, and create a center hole. Make sure to stretch it out some so that it doesn't close up completely during boiling & baking. 
7. Place the shaped bagels on a baking sheet. Cover with plastic wrap, wet towel or place into your fermentation box. Allow to second rise for 1-4 hours until nice and fluffy.
8. Preheat oven to 425F (220C)
9. Bring a large pot of water to a boil. Add baking soda and sugar. 
10. Carefully add about 3 bagels to the boiling water, using a slotted spoon. Leave in for 1 minute, flip and allow to boil for one more minute. 
11. Remove from the pot, let the excess water drip off, and dip on your favorite bagel seasoning - or leave plain. 
12. Place bagels onto a parchment paper-lined sheet pan. 
13. Bake for 20-25 minutes or until the outside of the bagel is golden brown on top. 
14. Place warm bagels on a cooling rack until cooled off. 
15. Next day, store in an airtight bag.