Marenian Tavern Story: Patty and the Hungry God

I unlocked this midway through the second week of winter in the first year.

I made selling dishes using Auroch's Tongue a priority, as the stew and the steak go for about two grand a piece, and they sell easily during winter.

At this point in the game, Auroch's Tongue can be got by fighting beast type enemies and using the "Slashing Down" skill on them to increase their drop rate. The drop rate is still rare, however. Also make sure to buy as much Black Pepper as you can from the wandering trader whom visits Cookoro from time to time, and from the store here too. You'll need it to combine with salt and make "mixed salt".

Fill out the rest of the ingredients list with the most expensive items you can make plenty of (the second tab across the top sorts by most expensive dish).

Filling out the menu this way netted me 114,000g.

This was done when I only had the one menu upgrade, meaning I could list a maximum of eight dishes at a time to be sold. If you've bought the ten slot menu from the in-game, in-menu shop using 60 jewels, it will be even easier.