Set a 12-inch skillet over medium-high heat. Add 2 tablespoon butter and 1 tablespoon neutral oil. When the butter melts and foams, add the seasoned potatoes in an even layer. Press them down with your spatula so they make good contact with the pan.
Cook the potatoes for 8 minutes without fussing much. You want the bottoms to brown. If you stir constantly, you will delay crust formation.
Stir and spread the potatoes back into an even layer. Add the onion and bell pepper, then cook for 6 minutes, stirring every so often, until the vegetables soften and the potatoes are browned in spots. If the pan looks dry, add 1 teaspoon oil; dry pan equals scorched bits instead of crisp.
Add the garlic and cook for 30 seconds, just until fragrant. Garlic burns fast, so this is a quick cameo.
Crumble in the canned corned beef. Break it into small chunks with the spatula and fold it through the potatoes. Drizzle in the worcestershire sauce.
Now commit to crisp: spread the hash into a compact, even layer and press it down firmly. Let it cook for 5 minutes, undisturbed, so the underside develops a deep brown crust. If you like extra crunch, go 1 minute longer, but watch the heat.
Flip sections of the hash (you do not need a perfect flip) and press down again. Cook for 2 minutes to re-crisp and heat through. Taste a small bite and adjust with a pinch of salt only if it truly needs it.