Mix ingredients of starter in large mixer bowl; mixture will look somewhat like pancake batter. Cover with plastic wrap and let stand at room temperature for 1-2 hours until mixture is bubbly and increased to nearly double in size.
Add remaining yeast to starter. Place dough hook on mixer and gradually add remaining flour, gluten, salt and brown sugar into starter and mix on low speed for 6-8 minutes. Then stop and cover machine with kitchen towel, allowing dough to rest for 5 minutes. Transfer dough to counter and hand knead for 10-12 minutes. Add flour as needed to create a smooth and pliable texture, not tacky.
Separate the dough into 12 pieces, formed into small balls as you would make for dinner rolls. Cover with plastic wrap and let stand for 20 minutes.
To form bagels, flatten each ball, roll into cylinder shape about 9 inches long. Wrap around your hand and seal edges by pushing your fingers into your palm. Transfer bagels to two baking pans which have been lined with parchment paper and sprayed with cooking oil. Cover with plastic wrap and refrigerate overnight (or longer- up to two days.).
On the day of baking, remove bagels from refrigerator and bring to room temperature while you preheat oven to 450 degrees F for one hour. Set a wide pot to boil with four inches of water. When oven is heated and bagels are ready, add baking soda and sugar to boiling water. With slotted spoon, place 3 or 4 bagels into pot. Count to ten and flip bagels and count to ten again. Remove bagels and drain in colander. Repeat process.
Place boiled bagels onto two baking sheets which have been lined with parchment paper and dusted with cornmeal. Put pans into oven and set timer for 8 minutes. Rotate pans and set timer for 8 minutes more. Check for doneness and continue baking up to 4 minutes more according to your preference. The bagels should be nicely browned on top and dark crust on bottom.