To a small saucepan over medium heat, add the jalapeños, peaches, sugar, apple cider vinegar, mustard seeds, celery seeds, turmeric, salt, garlic powder, and ginger.

Bring to a light boil and simmer for about 5 minutes, stirring occasionally, until the jalapeños begin to soften and crinkle up around the edges. 

Remove from the heat and use a slotted spoon to transfer the peaches and jalapeños from the saucepan to a mason jar (don't transfer the syrup! Let it drain through the slotted spoon before transferring the jalapeños & peaches). 

Return the syrup to medium-high heat and bring to a boil, then reduce the heat to medium and simmer for 8-10 minutes. To test if the syrup is done, place a metal spoon in the freezer for about a minute, then place it into the syrup and remove it. If you can run a finger down the back of the spoon and it leaves a clear trail and doesn't immediately run back together, your syrup is done.

Remove from heat and let the syrup cool for a few minutes, then pour the syrup over the peaches and jalapeños in a jar. Let it cool to room temperature, then place a lid on top and store in the refrigerator.