Preheat oven to 425°F (220°C). Line a large rimmed baking sheet with parchment paper. Pat potato cubes dry with paper towels. Toss with olive oil, garlic powder, onion powder, chili powder, salt, and pepper until evenly coated. Spread in a strict single layer with space between pieces.

Roast for 35 to 45 minutes, tossing firmly every 15 minutes, until deeply golden and crispy. For extra crispiness, increase oven to 450°F for the final 5 minutes and watch closely.

While potatoes roast, brown the ground beef in a large skillet over medium-high heat. When half browned, add the diced onion and minced garlic. Continue cooking until fully browned. Drain excess grease.

Stir in taco seasoning and 1/4 cup water. Reduce heat to low and simmer for 5 minutes until the sauce is thick and glossy.

Melt butter in a small saucepan over medium heat. Whisk in flour and cook for 1 minute until pale and paste-like. Slowly whisk in the milk in a thin stream until smooth. Cook over medium heat, whisking continuously, until thickened to coat the back of a spoon, about 3 to 4 minutes.

Remove cheese sauce from heat. Stir in the freshly grated cheddar and chili powder until completely smooth and velvety.

To assemble, add a generous base of crispy roasted potatoes to each bowl. Top with a scoop of taco meat. Drizzle warm cheese sauce over everything.

Finish with diced tomatoes, raw onion, fresh cilantro, a dollop of sour cream, sliced jalapeños, and a squeeze of fresh lime juice.