Preheat your oven to 180° C (350° F), get out a 9x13 baking dish.
Heat a pot of salted water to boiling, then add the macaroni and cook until almost tender, drain.
While the macaroni is cooking, add the sour cream, eggs, pepper, and nutmeg to a mixing bowl and mix together.
To the mixing bowl, add the cubed ham and peas and mix together.
Heat the oil in a non stick pan, when hot, add the onion and garlic, sauté until onion is softened. Drain any oil, then add the onion to the mixing bowl and mix in.
When the pasta is cooked and drained, add the sour cream mixture to the macaroni and mix together.
Pour mixture into the 9x13 baking dish and spread out evenly.
Top with the Cheddar cheese evenly.
Bake for 30-35 minutes or until the top is just starting to brown.
Serve and enjoy.