How can I achieve the same flavor and texture as roasted garlic without an oven?
You can get the same result by frying the garlic in a saucepan of oil. 

Place peeled cloves in a saucepan and add enough light olive oil or canola oil to just cover the cloves.  Cook at medium to medium-low heat, stirring not too often until the garlic becomes golden brown. 

Strain the cloves into a strainer or colander to remove excess oil, but save as much of the oil as you can.  It is now filled with the lovely roasted garlic flavor, and is wonderful for sauces, salad dressings, and drizzling over cooked foods.

If you don't mind a less-neutral base oil, you can use good extra-virgin olive oil instead of light olive oil. The resulting infused oil will have an even richer flavor.