The only ingredient you need is pure maple syrup, so it's important you find good tasting maple syrup, witch is not easy to do, even here.
It is really simple to make. Cooking the syrup 13 degrees over boiling point and then mixing it until you get the right texture.
Handheld electric mixer
Glass of water
Pure maple syrup (about 2 cups)
Step 1: Calibrating Your Thermometer
Mine, today, told me just under the 100 line.
Ok, all this would make much more sens if my temperature grid was more precise... But anyway, I'll stop cooking the syrup a little under what would be the 113 degrees line...
If you stop it to soon, it will work, but not as well, you might get a butter that will "split" more easily and won't be as much homogeneous.
So precision will get you best result every time, but as you can see, it can work whit out precision tools.
Step 2: Cooking Syrup
Put about 2 cups (1 can) of maple syrup in your saucepan and start heating it at medium-high temperature. Watch it closely as the syrup will get foamy when it starts boiling, and it can get out of control and spill everywhere. You don't want that. It's sticky.
When it get foamy, use your brush to put water on the sides of the pan to stop the foam from going up. If it's not working, lower the temperature to medium or remove your pan to stop the panic.
Watch the thermometer, it will start boiling around 100 (...) and remember, you want to stop it at 113... (refer to step 1 if it's not clear enough)
When it's at 113, stop the fire, your done cooking the syrup.
Now have a break for 3 hours. Let it sit in the fridge (or overnight on the counter). The texture will get "more solid" (?).
Step 3: Mixing
It is not as tricky if you have eaten maple butter before, as you will know what texture you want to get.
Be ready to mix for a good 20 to 35 minutes.
The color of the syrup will lighten as air get in the mix. Texture and taste will change slowly, real slowly. At first it will taste more like maple taffy and then the texture will get more like icing, with small "crystals" you can feel in your mouth.
Now it's all yours. You will have to try different texture. I prefer more grainy butter, but the rest of the family prefer smoother texture.
You are pretty much done, just fill up some jars, leave it in the fridge. Use it on your toast the next morning, it's fabulous.
Leaving the sticky cookware in warm water overnight is the best way the clean it.