How to minimise sugar in meringue

Technically, the minimum ratio of sugar is zero. You can definitely create a stable meringue without any sugar at all, although you'll have to mind your conditions and preparation - use a spotlessly-clean bowl, room-temperature egg whites (separated when chilled), initially foamed up on low speed with an acid such as vinegar or cream of tartar, superfine sugar (if you're using any at all) added very slowly after the soft peak stage, and a starch (e.g. corn starch or icing sugar) at the end for added stability.

The main problem, of course, is that as you allude to, when you bake it you'll basically end up with dried-out egg. It won't have any flavour at all. If you're just reducing the sugar then maybe this isn't a problem. If you're trying to eliminate the sugar entirely or almost entirely then you need to replace it with something - generally, a savory bomb, like very old cheese (for example Reggiano and chives), or very dark chocolate if it must be a dessert.

To do that, just grate or finely chop the strong/savory elements, whip the eggs up to the shiny peak stage, and fold in the shavings at the very end. The meringue will hold up.

But again, and I'm going to repeat myself here - you don't need a lot of sugar for stability. You can easily halve the sugar measurement for a traditional meringue recipe and still have it come out OK (albeit less tasty) - especially if you make one of the more stable meringue types, such as an Italian meringue where the sugar is combined as boiling sugar syrup. But you don't have to do that; simply reducing the sugar is fine if you're careful.

I have found this method to achieve a decent meringue with less sugar:

Set a pan of water to simmer.

Using a metal bowl or the top of the double boiler, place your egg whites over the simmering water.Add about half the usual amount of granulated or superfine sugar and stir until the sugar is dissolved. I don't use a thermometer.

Take the egg white sugar mix back to the mixer bowl , add a small amount of something acid like cream of tartar or lemon juice and start whipping. Continue whipping until the bottom of the bowl is cool even if the peaks look good.

You can add additional sugar, but if you do so, use confectioner's sugar (powdered sugar, or sugar which has a bit of corn starch/corn flour) in it. That avoids graininess. However, confectioner's sugar tastes sweeter to me.

I add flavor such as vanilla once the peaks have formed.

This meringue also can form the basis for a butter cream frosting by adding room temperature but sill cool butter in one tablspoon increments after the stiff peaks form.

I found that by adding some vanilla extract at the end that it added flavor to compensate for less sugar.

It's also possible to replace some (or all) of the sugar with Isomalt. It behaves a lot like sugar, but isn't sweet.

You could always use brown sugar. Just dump everything in and whip it up. Make sure the equipment is spotlessly clean though. Brown sugar generally gives the meringue a caramel/toffee like flavour but it's richer and far less sweeter than a normal meringue.