Bake the sliced potatoes at 425°F for 45 minutes, flipping every 15 minutes. Crank the heat to 450°F and bake another 10-15 minutes until brown and crispy.
In a skillet, cook the ground beef with ¾ of the yellow onion and the taco seasoning, adding 2 cups of water.
In a saucepan, melt the butter and whisk in the flour. Gradually add the milk, salt, pepper, and chili powder, cooking until thickened.
Assemble the potato bowls by layering the crispy potatoes, ground beef mixture, cheese sauce, remaining ¼ onion, diced tomato, cilantro, and Taco Bell sauce.
