Preheat ⅛ to ¼ cup of olive oil in a nonstick pan to medium heat for a few minutes.
Add the diced potatoes and cook until browned and crispy in most spots.
Cover the potatoes while they cook to help them cook faster from the inside. Transfer potatoes to a plate lined with paper towels to drain, set aside.
Add the ground beef to that same skillet and heat to medium/high.
Season beef with 1 teaspoon salt, 1 teaspoon garlic powder, 1 teaspoon cumin and ½ teaspoon pepper. Cook for 8 to 10 minutes until nicely browned.
Add the garlic and onion, continue cooking for 2 to 3 minutes.
Add tomatoes, serranos, ¼ cup water, salt and oregano to the blender and blend until smooth.
Pour tomato mixture into picadillo.
Let it come to a boil and taste for salt.
Fold in the potatoes and stir until well combined.
Taste for seasonings and continue cooking at a low simmer until sauce thickens and reduces, 7-10 minutes.
Remove from heat.
