In large skillet over medium, heat oil. Add onion and 1/4 tsp salt; cook for 5 minutes, or until softened. Add sweet potato and garlic; heat just until potato is tender, about 2 minutes.
In large bowl, whisk together eggs and milk. Stir in red bell pepper, cheese, thyme, remaining 1/4 tsp salt, and black pepper. Stir in cooked vegetables. Divide among 16 mini-sized greased muffin cups. Bake until egg cakes are set, about 15 minutes. Let cool for a couple of minutes before unmolding.
Notes
Per serving: 223 calories; 12 g protein; 10 g total fat (4 g sat. fat); 22 g total carbohydrates (6 g sugars, 3 g fiber); 436 mg sodium