Wait till it's late at night, you're all alone and feeling kinda hungry, then go look at food blogs. Find one which comes with the most pleasing photo:
Drool over the photo until you've forgotten all about how lazy you really are, and are determined to sink your teeth into the frozen pie, no matter what it takes. You will be motivated enough to make it, even if you can't get all of the required ingredients.
Cut a slice, put some Elvis on, and enjoy...
Note: If you're seriously underweight, repeat step three as many times as you deem necessary!
(Note to self: Try not to post a professional-looking shot in the same entry as one taken in a hurry, under poor lighting, and of an object not half as pretty-looking)