Preheat oven to 425°F (220°C).
Bring a large pot of salted water to a boil. Add diced potatoes and parboil for 5 minutes until slightly tender but not fully cooked. Drain and let cool.
In a large mixing bowl, combine cooled potatoes, diced onion, diced green bell pepper, olive oil, garlic powder, smoked paprika, dried thyme, salt, and black pepper. Toss until all ingredients are evenly coated.
Spread the potato mixture in a single layer on a large baking sheet lined with parchment paper.
Bake for 20-25 minutes, stirring halfway through, until potatoes are golden brown and crispy.
Allow the potatoes to cool completely on the baking sheet.
Divide the cooled potatoes into freezer-safe airtight containers or resealable freezer bags, removing as much air as possible.
Label and freeze for up to 3 months.
To reheat, bake frozen potatoes at 400°F (205°C) for 15-20 minutes or until heated through and crispy.