Levels are very simple to add, i only added 1 to show you how all mechanics works,you simply use a variable to track the level number the player is currently playing, and then play with the Goal variable number, so level 1 goal is $700 level 2 goal is $800 for example...etc
and the dishes are just sprites, the assets I used in this template contain these 3 dishes only, you can draw your own and add as much as you like.