There are two types of
solar ovens.
A box with sides and a glass lid holds the heat in, so flat black interior. Also use black cookware in it as well, so it absorbs the heat.
If you are thinking of the satellite-style that is silver and holds a pot up off the center of it, that focuses the heat on one point, which hopefully, when done right, is under the pot. It's tricky to move this one and keep it focused, especially if you are on rough ground. It's more dangerous to kids/animals because the heat source is open, the surface is shiny and kids want to put their hands on it, which is a serious mistake if it is up in the 350 F range. And small kids, or kids playing ball around it can back into it, or hit it with a ball, and it's quite vulnerable.
We use a box style for picnics and keeping food warm, and that's where it's important to keep people away from it.
Both styles need to be tipped up into the sun at the angle of the season, and both need to be moved every so often to follow the sun across the sky, otherwise they lose heat.
An important distinction: Permaculture is not the same kind of gardening as organic gardening.
Mediterranean climate hugel trenches, fabuluous clay soil high in nutrients, self-watering containers with hugel layers, keyhole composting with low hugel raised beds, thick Back to Eden Wood chips mulch (distinguished from Bark chips), using as many native plants as possible....all drought tolerant.