01 - Heat a large skillet over medium-high heat. Arrange the sliced kielbasa in an even layer and cook for 4–5 minutes, turning occasionally, until nicely browned on both sides. Transfer to a plate and set aside.
02 - Melt the butter in the same skillet. Add the diced onion and bell pepper, sautéing for 3–4 minutes until softened. Stir in the minced garlic and cook for 1 minute until fragrant.
03 - Add the sliced potatoes to the skillet along with the smoked paprika, black pepper, salt, and dried thyme. Toss to coat evenly. Cover with a lid and cook for 10–12 minutes, stirring occasionally, until the potatoes are fork-tender.
04 - Return the browned kielbasa to the skillet and toss to combine with the vegetables. Sprinkle the shredded cheddar evenly across the top. Reduce heat to low, cover, and cook for 2–3 minutes until the cheese is fully melted and bubbly.
05 - Scatter chopped fresh parsley over the top, if desired. Serve immediately while hot.