In a mixing bowl, combine 1 cup of warm water, 2 1/4 tsp active dry yeast, and 1 1/2 tbsp sugar. Let it sit for about 5 minutes until frothy.
In another bowl, whisk together 3 cups all-purpose flour, 1 tsp salt, and 1 tsp garlic salt.
Gradually add the yeast mixture to the dry ingredients and stir with a wooden spoon until the dough begins to come together.
Fold in 2 tbsp chopped jalapenos and 1 1/2 cups shredded cheddar cheese evenly into the dough.
Transfer the dough to a floured surface and knead for 5-7 minutes until smooth and elastic, adding flour if sticky.
Place the kneaded dough in a greased bowl, cover with plastic wrap, and let rise in a warm area for about 1 hour until doubled in size.
Punch down the dough and divide into 8 equal pieces. Roll each piece into a ball and poke a hole through the center, stretching to form bagels.
Fill a large pot with water, bring to a simmer, and add 1 tbsp brown sugar. Boil each bagel 1-2 minutes per side, then remove with a slotted spoon to a baking sheet lined with parchment paper.
Preheat oven to 425°F (220°C). Spray bagels lightly with cooking spray and bake for 20-25 minutes until golden brown.
Remove bagels from oven and let cool on a wire rack. Enjoy fresh or toasted with butter or your favorite spread.