Peel and slice peaches. You can peel the peaches using the boiling water method, or just carefully slice them off with a paring knife. Set aside.

In a medium bowl, whisk together the sugar, cornstarch and cinnamon.

Divide about 1/3 peach slices and add to bowl with cornstarch mixture. Pour in water and stir to combine.

Crush peaches with potato masher or puree using an immersion blender. Stir. Mixture will be pale and cloudy.

Microwave on high for 3 minutes. Stir. Return to microwave for 2 more minutes. Stir again. Microwave for 2 final minutes.

While mixture is cooking in the microwave, chop the remaining peaches into very small pieces.

Stir in butter and vanilla. Mixture will look like thin jam. Pour in remaining chopped peaches. Stir.

Microwave entire mixture for 1 minute. Stir. Syrup will be thick. Transfer to jar & refrigerate until ready to use. Heat for 1-2 minutes before serving.