Preheat oven to 350°F.
In a small bowl, combine eggs, milk and sour cream, season with salt and pepper to taste. Chop tomatoes and finely chop green onion.
In a skillet, heat butter and oil over medium heat. Add egg mixture, add the tomatoes and green onion. Cover skillet with lid and cook until almost cooked. Remove from heat. (Do not overcook the eggs.)
Cut the eggs into six equal parts.
Combine all the ingredients for the honey Dijon sauce. Set aside.
Slice croissants in half. Top one side with ham, cheese and egg. Evenly distribute sauce between all six croissant sandwiches.
Place sandwiches into a casserole dish. Bake for 15 minutes or until cheese melts and tops of croissants are crispy and golden. (If needed, cover baking dish with foil for the cheese to completely melt and so the tops of croissants don't burn.)