Preheat oven to 180°C (350°F). Lightly grease your baking dish.
In a large bowl, whisk together eggs and milk.
Add gluten-free flour and baking powder. Use an electric mixer to combine - this helps eliminate any lumps, but you can also whisk by hand.
Stir in cheese, onion, bacon or ham and corn, salt and pepper.
Pour mixture into the prepared dish and smooth out the top, placing sliced or halved cherry tomatoes gently on top.
Bake for 35–40 minutes, or until golden and centre is set.
Let cool slightly before slicing. Serve warm or chilled.