Start by cutting boneless, skinless chicken thighs into bite-sized pieces. In a bowl, combine the chicken with salt, ground black pepper, and cornstarch, tossing everything until the chicken is evenly coated. Set the seasoned chicken aside as you prepare the sauce.

In a separate bowl, whisk together low-sodium soy sauce, water, brown sugar, and minced garlic until fully blended. This mixture will serve as your glaze, adding a deliciously sweet and savory element to your Crispy Spicy Jalapeño Chicken. Set the sauce aside until you're ready to cook the chicken.

Heat a deep pot or fryer and pour in vegetable oil, enough to submerge the chicken pieces comfortably. Preheat the oil to 315°F (157°C). Carefully add the seasoned chicken in batches, frying for about 5-6 minutes or until the chicken turns pale and just cooked through. Use a slotted spoon to transfer the chicken to a wire rack to drain excess oil.

Once all chicken pieces have been initially fried, increase the oil temperature to 350°F (177°C). Fry the chicken again in batches for an additional 3-4 minutes, until each piece turns golden brown and crispy. This double frying technique ensures a crunch that elevates your Crispy Spicy Jalapeño Chicken. Drain on a wire rack again to maintain that crunchiness.

In a skillet over medium heat, pour the prepared sauce and bring it to a bubbling simmer. Carefully add the double-fried chicken pieces and freshly sliced jalapeños to the pan, tossing everything together for 1-2 minutes until all the chicken is well coated with the glaze.

Once thoroughly combined and warmed, transfer your Crispy Spicy Jalapeño Chicken to a serving platter. Enjoy the vibrant flavors, and watch as your family dives into this homemade takeout delight!