Just use (browser) → Import (Steam). The entire process takes less than 30 seconds. There is no need to start over from zero on Steam. Pro tip: If you plan to play mainly on Steam, import your browser save once, then use Steam’s own cloud saves (which work automatically between different computers running the Steam version). You won’t need to re-export from the browser again unless you go back to playing in a browser.
Short answer: Yes, absolutely. You can transfer your save file from the browser version of Cookie Clicker (on any website, like the official DashNet or Orteil’s version) to the Steam version, and vice versa. can i import my cookie clicker save to steam