Making marshmallows is more science than art, IMO. The art comes in the flavoring, but before you go substituting sugars, you MUST pay attention to the science.
1. Tender marshmallows need a combination of glucose and fructose, heavier on the glucose.
2. Regular corn syrup, or if you can find it "golden syrup" or "glucose syrup" is almost entirely glucose, and before you go tossing in lots of honey or maple or what have you, you REALLY need to have one of the primary sugars be glucose, otherwise what you get isn't quite marshmallow. Tough is a good word for it.
3. Use a candy thermometer. Trust me.
4. Honey is fructose. Agave is fructose. Maple is sucrose (molecularly bonded glucose and fructose). Rice syrup is, IRC, mostly maltose, which is a very different sugar. I'm happiest with the recipe's proportion of glucose to sucrose, texture wise.
5. Saying you want "sugar free marshmallows" is saying like you want "Oxygen free air." It won't happen. You may manage to source your glucose and fructose from something other than corn or sugar cane, but really, you're going to have to use glucose and fructose if you want to have it coming out really marshmallowish. Vegan marshmallows are also supposedly nearly impossible to make at home, because the gelatin substitutes available don't work right with the hot sugar.
All that said...
I make my marshmallows with Karo corn syrup (HFCS free) and organic raw cane sugar. They are FANTASTIC. It is entirely possible to overdo. They make people who hate store-bought marshmallows love homemade marshmallows. And once you have mastered the "base" technique, you can experiment with flavorings. Good marshmallows are one of the most delicious things you will ever eat.
I base my recipe on Martha Stewart's recipe, but with some significant changes.
Tools needed:
Candy thermometer
Stand mixer with a good motor
2 quart saucepan
Measuring spoons, cups, heat-resistant spatula, chopping knife
9x13 pan
Plastic wrap or foil
Ingredients:
3 packets gelatin
1/2 cup water very cold
AND 1/4 cup water (temp not so important)
1 cup unbleached granulated cane sugar
1 cup brown sugar and/or sucanat (I might use 1/4 cup sucanat and 3/4 cup packed brown sugar)
2/3 cup corn syrup (non-HFCS, just plain corn syrup or glucose syrup. Light is fine.)
1/4 teaspoon sea salt
Unflavored cooking spray
Confectioners' sugar and/or cocoa, carob, and/or tapioca, potato starch, to taste.
Flavorings and additions:
Vanilla Peppermint (family favorite)
1/4 teaspoon peppermint extract
1-2 teaspoons vanilla extract
For a neat texture, you can also crush candy canes (natural, preferably) and line the pan with them before you pour the marshmallow in.
Root Beer Pecan (friend favorite)
1 teaspoon root beer flavoring (I make my own blend with a *tiny* bit of wintergreen essential oil, a fair amount of anise extract, licorice flavor, peppermint (tiny amount), ginger, and clove. I think. I don't remember exactly. Keep in mind that sassafras, sarsparilla, and wintergreen can be toxic in large amounts, but are found in most good root beers in tiny quantities. I've made root beer extract a couple of times and it is always different and always good, I test it in soda water with organic sugar before marshmallowing it.)
1 teaspoon vanilla
Crushed pecans in the pan before the marshmallows go in.
(For this I use dark corn syrup and dark brown sugars)
Directions:
Spray the 9x13 pan liberally with cooking spray
In the stand mixer bowl, pour the 1/2 cup cold water and sprinkle 3 packets of gelatin over the surface
In the saucepan, put the sugars and corn syrup and 1/4 cup water. Stir until mostly blended, turn on heat, medium high or high. Clip the candy thermometer to the side of the pan so the tip is not touching the side or bottom of the pan but is in the sugar mixture. While the sugar mixture is heating, do not stir. Heat until candy thermometer reads 238-240 degrees (soft ball stage).
Remove syrup from heat quickly, turn the mixer on, and carefully pour the sugar syrup in.
Turn mixer on high.
All parts of this process are important, but this is the "secret" most of the online recipes don't tell you and will in some cases make the difference between success and failure in marshmallow making.
Put on a couple of oven mitts on, and holding the bowl's handle with one hand and the other hand under the bowl to stabilize it, lift the bowl up a small amount so that the beaters hit the sides and bottom. This will help all the gelatin to mix in well. Do this every 1-2 minutes for the first half of mixing, then every 3-4 minutes during the last half.
Beat the mixture for 11 minutes, then sprinkle in the salt and add in the flavoring extracts and beat for 1 more minute.
Pour the mixture into the prepared pan. Spray the plastic wrap or foil (same size as the pan is needed) with cooking spray, put it on top of the mixture, and use it to smooth out the marshmallow.
Let sit for at least two hours, as long as 12.
Cover a surface (counter or cutting board, be prepared for powdery mess) with one of the following mixtures, to taste:
Pure confectioners sugar (sweet and simple)
or
A mixture of confectioners sugar and cocoa (1:1 ratio approximately) (if you like chocolate, also works well in hot cocoa)
or
Pure carob powder (no need to add sugar, carob is sweet)
or
A mixture of powdered sugar and tapioca or potato starch (makes it less sweet overall)
or
Plain potato or tapioca starch (good mouth-feel, doesn't add sweet to the already-sweet marshmallows)
Remove the plastic wrap or foil from the pan, cover your hands with cooking spray, and turn the marshmallow out onto the powdered surface.
Spray a long chopping knife with cooking spray.
To cut marshmallows, press the knife straight down, rock it a tiny bit, the marshmallow will separate after a second. Make all of your cuts in one direction, then cut in the other direction to make small squares, we find 1x1 inch squares to be about perfect, other people like 2 x 2 inch squares, but I find that unwieldy and large.
Turn each square in the powder until it is covered on all four sides.
I store them in a large ziplock bag, but they will go well in tins too. They are freshest in the first 3 days or so, but will last up to a month.
These are delicious for s'mores and cocoa, but also just for eating, they are much more flavorful than store-bought marshmallows, even so-called "homemade" ones.
To make rice crispy treats, put a bit of shortening or butter (I use non-hydrogenated shortening) in a metal bowl, pour the marshmallow directly onto that from the mixer, then add rice crispies or other crisp cereal, stir until coated and then pour into pans.
Other flavoring combinations can be used. Suggestions:
Just vanilla (use 2 teaspoons)
Almond (use 1/2 - 1 teaspoon)
This recipe is adapted substantially from Martha Stewart's recipe for Peppermint Marshmallows.
I find that while her pure-sugar version is whiter, mine tastes better with the brown sugar. Much richer. And she just adds peppermint, not peppermint and vanilla. The vanilla gives a richer, "rounder" flavor and takes a bit of the bite from the peppermint, it's truly delicious.
Please note: A candy thermometer is really important for this. You can get them for as little as $3-$4. My favorite cost $9.99 and is very long, it looks like an oversized meat thermometer. Meat thermometers will not work, as they only go up to 220 degrees and we need at least 238. NO MORE than 250, period, or you will get taffy. Trust me on this.
If you want to put in maple syrup, do not try to substitute it for the corn syrup, as the texture will be very odd (nougat comes to mind.) It can be substituted for part of the table sugar and a bit of the water. The maple marshmallows we made were extraordinarily sweet, far sweeter tasting than most of the others I've done. Mostly a waste of maple syrup, if you ask me.