Sabbath-mode ovens have a switch that:

• Keeps the light on or off (according to the way you have set it), regardless of whether the oven door is open or closed,
• Makes a forced delay in the heating elements' turning on after the door is opened so that the heating element never goes on while the door is open, and
• Shuts off the timer and digital display.

Sabbath-mode ovens do not permit any normally forbidden cooking-related actions on Shabbat. You may not ever cook food on Shabbat, even in such an oven (or any other way)!