The secret ingredient

There were two secret ingredients that made this evening's cottage pie delicious. Having put some potatoes on to boil, I set to work to make comfort food.
I chopped and fried an onion and a carrot in beef dripping from Sunday's roast. When they were soft, I added a couple of chopped portobella mushrooms, and put some salt and black pepper in the mix.
Then I ground the leftover beef, mixed it in with the vegetables and moistened it with the leftover gravy and some red wine. Now it's time for the secret ingredients. Freshly ground white pepper and tomato ketchup add spice and sweetness.
When the potatoes were done, I mashed them roughly with some butter and salt, then built my cottage pie, slathered on some more butter and shoved it in the oven.
When the mashed potato was golden and crispy, I served it with peas cooked with butter and basil.
I never eat shepherd's pie, because I grew up around shepherds and think it's cruel to eat them.