Cut potatoes in half and then half again.
Cut peppers into 1-2 inch squares.
Cut onion in half, then cut the halves in half and half again so you have basically cut the onion into square pieces like the peppers.
Finely chop garlic. Melt butter in a mixing bowl in the microwave. Add 1-2 T olive oil. Add vegetables and season. Toss gently to evenly coat vegetables.
Line a baking sheet with foil and spray with olive oil spray. Put vegetables on baking sheet and spread into an even layer. Bake at 425 for 25 minutes. Re move and turn oven to 500. Toss veggies gently and return to 500 degree oven for 15 minutes until just starting to turn dark and crisp on the edges. Serve immediately. Makes 2-4 servings. Double quantities as needed.