Preheat oven to 375°F and lightly grease a baking dish.

Heat olive oil in a pan over medium heat.

Add onion and cook until softened.

In a large bowl, combine chopped nuts, breadcrumbs, carrots, potato, cooked onion, rosemary, salt, and black pepper.

Whisk eggs and milk together and add to the mixture.

Mix until evenly combined.

Press mixture into the prepared baking dish.

Bake for 50 minutes until firm and lightly golden.

Let rest briefly before slicing.