Grab a sturdy saucepan and combine your allulose sweetener, brown sugar replacement, and water. Place it over medium heat, stirring gently as it warms up. Bring the mixture to a boil, continuing to whisk until all the sweeteners are completely dissolved.
Reduce the heat to medium-low and let your syrup simmer for about 5 minutes. Keep a close eye on it during this stage to make sure it doesn't burn.
Next, stir in the butter until it's fully melted and blended into the syrup. Bring the mixture back to a gentle simmer and continue cooking, stirring occasionally, until it starts to thicken slightly and gets a lovely, richer golden color.
Remove the saucepan from the heat. Whisk in the maple extract and, if you're using it, the pinch of salt.
Allow your delicious homemade syrup to cool completely to room temperature. Once it's cool, transfer it into a clean glass jar for easy storage. Enjoy your sugar-free treat!