Place blueberries in a small saucepan over low heat. Gently stir and press to release juice, but do not fully cook. Let cool.

In a large bowl, mix lukewarm water, sugar, and yeast. If using active dry yeast, let sit for 5–10 minutes until foamy.

Add bread flour, salt, vanilla extract, and cooled blueberries with juice to the yeast mixture. Mix until a thick, slightly sticky dough forms. Add a splash of water if needed.

Knead the dough by hand or in a stand mixer for about 10 minutes until smooth and elastic.

Place dough in a lightly oiled bowl, cover, and let rise until doubled in size, about 1–1.5 hours.

Punch down the dough and divide into 8 equal portions. Shape each into a ball, rest 5 minutes, then poke a hole in the center and stretch into a ring.

Place shaped bagels on parchment-lined trays. Let them proof for about 30 minutes.

Bring 2 liters of water to a boil and add honey or brown sugar. Boil bagels one minute total, flipping halfway through.

Bake at 425°F (220°C) for about 20 minutes or until golden. Let cool before slicing.