There are several ways you can get Cash in Star Chef 2:

1) Team Chest - Team works collaboratively to win a Team Chest
2) Completing Chef Journal Chapters
3) Completing Achievements
4) Watching video ads on the billboard next to Supermarket (Only on mobile platforms)
5) Spin Wheel 
6) Team Championship Race
7) Mini-games

In addition to all that, you can always buy Cash by tapping on the "+" button next to your Cash balance at the top of the screen.