Step 1

In a large, shallow saucepan, combine the onion, garlic, and water. Cook over medium heat until the onion is translucent and softened, about 5 minutes.

Step 2

Add the ketchup, apple cider vinegar, honey, and mustard powder. Continue cooking for 20 minutes, until the sauce is thickened. Season with salt and pepper.

Step 3

Remove the pan from the heat. Using an immersion blender, puree the sauce until smooth. Let cool completely, about 25 minutes.

Step 4

Transfer to a clean airtight container and store in the refrigerator. The barbecue sauce will keep for up to 4 days.

Step 5

Enjoy!