Wash and peel the russet potatoes if desired. Cut them into 1/2-inch dice (about 3/4–1 cm). Place the diced potatoes in a large bowl of cold water and let them sit 5–10 minutes to remove excess surface starch, then drain and pat very dry with a clean kitchen towel or paper towels.

Prep aromatics

Peel and finely dice the yellow onion to yield about 1/2 cup. Core, seed, and dice the green bell pepper to about 1/2 cup. Mince the garlic finely. If using parsley, finely chop and reserve for finishing.

Fats & Seasoning

Par-cook potatoes

To ensure tender interior, par-cook the diced potatoes by microwaving or simmering briefly. Microwave method: place dried potato dice in a microwave-safe bowl with 2 tablespoons water, cover loosely, and microwave on high for 3–4 minutes until just tender but not falling apart. Drain any liquid and pat dry. Stovetop blanching: bring a pot of salted water to a boil, add potatoes and cook 4–5 minutes until slightly tender, then drain and dry thoroughly.

Heat pan

Heat a large heavy skillet (cast-iron preferred) over medium-high heat. Add 2 tablespoons vegetable oil and 1 tablespoon butter (if using) and let the butter melt and foam but not burn. The fat should shimmer and be hot enough that a small potato piece sizzles on contact.

Fry potatoes

Add the dried, par-cooked potato dice in a single layer (work in batches if needed to avoid overcrowding). Let potatoes cook undisturbed for 3–4 minutes to develop a golden crust. After the bottom is browned, flip and move pieces with a spatula so other sides make contact with the pan. Continue frying 8–10 minutes, stirring or flipping occasionally, until potatoes are golden-brown and crisp on most sides and tender through when pierced with a fork.

Add vegetables & season

When potatoes are mostly browned (about 5–7 minutes into frying), create a small space in the pan and add the diced onion and bell pepper. Sauté together with the potatoes for 3–4 minutes until onion is translucent and peppers are softened. Add the minced garlic in the last 30–60 seconds to avoid burning, stirring constantly.

Season & finish

Sprinkle kosher salt, black pepper, smoked paprika, dried oregano, and red pepper flakes (if using) over the potatoes and vegetables. Stir to combine and cook 30–60 seconds so spices bloom. Taste and adjust seasoning. Remove pan from heat and stir in chopped parsley if using.

Serve

Transfer home fries to a plate or keep warm in a low oven (200°F / 95°C) while you assemble breakfast sandwiches. Use as a side or tuck into sandwich with eggs, cheese, and meat as desired.