Heat the olive oil in a large skillet over medium heat. Add the diced potatoes and spread them into an even layer. Season lightly with salt and pepper, then cover the skillet and cook for 8–10 minutes, stirring once halfway through, until the potatoes begin to soften.
Uncover the skillet and continue cooking the potatoes for another 6–8 minutes, stirring occasionally, until they are fork-tender and starting to brown around the edges.
Add the diced onion, red bell pepper, and green bell pepper to the skillet. Cook for 4–5 minutes, stirring occasionally, until the vegetables are softened.
Stir in the sliced smoked sausage, minced garlic, and cayenne pepper. Cook for 3–4 minutes, stirring occasionally, until the sausage is heated through and lightly browned.
Taste and adjust seasoning as needed. Remove from heat and serve warm.
Cut potatoes evenly: Keeping the potato pieces similar in size helps them cook at the same rate and prevents some from burning while others stay undercooked.
Cover, then uncover: Covering the skillet at first helps steam the potatoes until tender, then uncovering allows them to crisp up.
Don’t overcrowd the pan: Giving the potatoes space helps them brown instead of steaming.
Add sausage later: Smoked sausage is already cooked, so adding it near the end keeps it from drying out.