01 - Place peeled and diced potatoes in a large pot, cover with salted water, and bring to a rolling boil. Reduce heat to medium-low and simmer for approximately 15 minutes until potatoes are easily pierced with a fork.
02 - While potatoes cook, heat a small skillet over medium heat. Add diced red bell pepper, jalapeño, and minced garlic. Sauté for 3 to 4 minutes until vegetables are softened and fragrant. Remove from heat and set aside.
03 - Drain potatoes thoroughly in a colander and return them to the pot. Mash vigorously until smooth and free of large lumps.
04 - Add milk, sour cream, and shredded cheddar cheese to the mashed potatoes. Stir continuously until the mixture becomes creamy and the cheese begins to melt.
05 - Gently fold in the sautéed bell pepper mixture, sliced green onions, ground cumin, smoked paprika, chili powder, salt, and pepper. Mix until evenly distributed throughout.
06 - Taste the mashed potatoes and adjust salt, pepper, or spices as needed to suit your preference.
07 - Transfer to a warm serving bowl, garnish with fresh chopped cilantro if desired, and serve immediately while hot.