A friend of mine introduced me to Ajisen Ramen in Willowdale almost two years ago, and I've been going back during cold weathered days with different people every time, and they all have enjoyed it.
My favourite ramen is the Pure Miso Veggie Tofu Ramen, it's filling and delicious. Getting a side of fried shrimp is always a good idea too. I haven't explored other options on the menu though, cause I always seem to be craving the same thing.
The staff is always really friendly, and come by regularly to fill up your glass of water or tea.
A few tips when visiting:
1) Don't sit in the booths, they're not stable and you can feel when the other person moves in the booth behind you.
2) Don't sit close to the door, especially when it's freezing cold outside.
3) Leave your coat and scarf in the car if you can, because your clothes are going to smell like fried food.