This page runs version 2.052 of Orteil and DashNet's Cookie Clicker, kept as its own copy next to the main game on the home page. It is the full modern game: twenty buildings from the Cursor up to "You", upgrades, achievements, golden cookies, sugar lumps, the dragon, seasons and ascension.
Click the big cookie on the left to bake. Spend cookies in the store on the right: buildings bake for you every second, and upgrades (the row of icons above the buildings) make them, or your clicks, stronger. Hold Ctrl to buy 10 at a time or Shift to buy 100. When a golden cookie flashes on screen, click it before it fades for a bonus such as a Frenzy or a lump of instant cookies.
Sugar lumps grow slowly over real time once you have baked enough. Spending one to level a building to level 1 opens its minigame: the Farm opens the Garden, the Bank opens the Stock Market, the Temple opens the Pantheon and the Wizard tower opens the Grimoire.
The Legacy button lets you ascend: the run resets, and what you baked turns into prestige levels and heavenly chips that you spend on permanent heavenly upgrades. Each new run then starts faster than the last.
Progress is saved automatically in your browser's local storage, in a separate save slot from the game on the home page. Clearing site data or using a private window loses it, so use Options → Export save now and then to keep a text backup you can import later.