01 - Cook macaroni in a pot of salted boiling water until al dente, approximately 6 minutes. Drain well and transfer to a bowl.
02 - In a saucepan set over medium heat, melt the butter. Sprinkle in the flour and whisk continuously for 1 minute to form a roux. Slowly incorporate the milk, whisking constantly, and cook until the mixture thickens, about 2–3 minutes.
03 - Stir in shredded cheddar cheese, garlic powder, salt, and black pepper until melted and smooth. Remove from heat. Mix in the drained macaroni and diced jalapeños. Cool fully, then refrigerate filling for at least 20 minutes until firm.
04 - In a mixing bowl, combine flour, instant yeast, salt, sugar, and warm water. Knead by hand or with a mixer for 5 minutes until a supple, smooth dough forms. Cover and allow to rise in a warm environment for 30 minutes.
05 - Set oven to 425°F and line a baking sheet with parchment.
06 - Bring 4 cups water and 1/4 cup baking soda to a brisk boil in a large saucepan.
07 - Divide the risen dough into 24 equal portions. Flatten each piece gently, add a heaping teaspoon of chilled mac and cheese filling to the center, pinch edges to seal completely, and roll into a uniform ball.
08 - Using a slotted spoon, carefully lower each filled dough ball into the boiling baking soda bath for 20 seconds. Transfer immediately to the prepared baking sheet.
09 - Brush each bite generously with melted butter and sprinkle with coarse salt. Bake for 12–15 minutes until golden and crisp. Serve warm for optimal flavor and texture.