The best way to keep your screen awake is by using the Web Wake Lock API.
To keep this "minimalist," we will use a small script that only runs when the user toggles a button.
HTML Semantics: Use a <label> properly associated with the <input type="checkbox"> so screen readers know what the toggle does.
Performance: Since this is a for static site, I recommend wrapping the JavaScript in a check or only loading it on recipe pages to keep your "minimal JS" philosophy intact.
Browser Support: Modern versions of Chrome, Edge, and Safari support the Wake Lock API. If the user is on an ancient browser, the try...catch block ensures nothing breaks; the screen will simply behave as normal.
If you are adding a section about this feature to your "About" or "Help" page:
"Enjoy a seamless cooking experience with our new 'Cooking Mode'. Toggle it on to keep your screen awake while following recipes, so you never have to touch your phone with messy hands again." (189 characters)