Improve efficiency cooking for one
Cook in large batches. The difference in time between preparing a single serving and, say, six servings is far, far less than 6x.

Pick the kind of meals that are okay to be refrigerated/frozen, or otherwise preserved, obtain a bunch of single meal sized tupperware boxes, make sure to have room in your refrigerator/freezer/pantry, and prepare quite a few meals of the same dish at a time. Eat one serving, leave the rest "for later".

Don't go about it the way you cook the next batch only when current one runs out, but stagger that - a week of cooking six servings of a new dish every day, leaves you with five more weeks worth of varied meals. Label your food, with type and date so that you don't leave anything too long and you know what you have (it's quite hard to tell some foods apart when they are frozen). 

You also don't need to make complete meals - you can prepare some more time-consuming ingredients in large batches, then make the readily made parts of the meal as needed, fresh - e.g. prepare several spaghetti sauces with meat, leaving cooking pasta and adding fresh seasoning as you prepare individual meals.