Peel, core, and chop the peaches into small, 1/2" cubes or thin slices depending on what you're using the filling for. I like small pieces for things like hand pies and larger pieces for peach pie or for use as a topping. Make sure you remove the skins or they will taste chewy and not have a great texture. You can also use frozen peaches which makes this even easier!
Add your sliced peaches to a large saucepan over medium heat. Add water, sugar, cinnamon, salt, and brown sugar.
Cook the mixture until the peaches are as soft as you like them. Fresh peaches will take the longest to cook.
Combine your ClearGel (or cornstarch) with the cool water and whisk together to make a slurry
Pour the slurry into your hot peach mixture and cook until the peach filling is nice and thick and turns clear. 3-5 minutes. Cook for one more minute to make sure the ClearGel is thoroughly cooked.
Remove the mixture from the heat and add in your lemon juice and vanilla extract. Stir to combine.
Now you can pour the hot filling into jars and can store your peach filling! Check out this blog post on canning peach pie filling for more detailed info. Storing in the fridge will work, but I prefer to let the filling cool down and freeze peach pie filling. The filling is good in the fridge for up to a week or 6 months in the freezer.