Heat a large nonstick skillet over medium-high heat. Add oil to pan; swirl to coat. Add potato, onion, and bell pepper. Cook 8 minutes or until onion is tender and potato just begins to brown, stirring occasionally.
Coat a 3-quart electric slow cooker with cooking spray. Place potato mixture in slow cooker. Combine eggs and next 3 ingredients (through black pepper), stirring with a whisk. Pour egg mixture over vegetables in slow cooker. Cover and cook on LOW for 2 1/2 hours or just until egg is set in center.
Turn off slow cooker. Let stand, covered, 10 minutes. Sprinkle with cheese, parsley, and capers. Cut into wedges.