I tried several methods and spent a lot of time composting several years back. Then, I did the math on how much I was generating in fertilzer/humus for the year compared to what I was investing in time. I was making something like $3 an hour. That didn't seem worthwhile to me. Now I just do what Brad does and bury my kitchen scraps in the garden.
Actually, some nitrogen is lost in the composting process. So, I think burrying is a more efficient use of nutrients (it won't get rid of pathogens like hot composting, but that's not as big of an issue when the material is 12" under the soil). Also, high carbon stuff will not affect your soil nitrogen if it is just a mulch. However, earthworms will slowly eat it from the bottom, up and turn it into humus. Now my motto is, "Burry the green, mulch the brown." It works best if you plan a fallow area (or areas) in your garden rotation where you can methodically burry scraps to enrich the soil.
As for bio char, my soil is really acid and is already high in organic matter. So, I need the liming effect of the ash more than I need the char. I just save the ash and whatever char there is from my fires to spread on the garden. I also save my bone scraps in a gallon bag in the freezer. When the bag gets full I dump it on a nice hot fire. Bone ash and char are about 30% phosphorus (most of which only becomes available slowly over time). As long as you live in a place where there is no mad cow disease, campfire heat should be enough to sterilize the bone. That is probably another of those things where I am not generating much in the way of a dollar value. But, if I was going to have the fire any way the time invested is negligible.