Peel 4 large sweet apples and 4 large tart apples. Halve and core them, then cut them into large chunks. Place the chunks in an electric pressure cooker or Instant Pot.
Add ½ cup water, 2 tablespoons lemon juice, and 1 teaspoon ground cinnamon and stir to distribute the cinnamon as evenly as possible.
Lock the lid on the pressure cooker and make sure the valve is set to seal. Set to cook for 5 minutes under HIGH pressure. It should take about 10 minutes to come up to pressure.
When the cook time is up, let the pressure naturally release for 20 minutes. Manually release any remaining pressure.
Uncover the pressure cooker. For chunky applesauce, use a potato masher to mash the apples to the desired consistency. For smooth applesauce, use an immersion blender to purée the applesauce directly in the pot until smooth, 30 seconds to 1 minute.
Taste the applesauce and, while it's still warm, add ⅓ cup packed light brown sugar, if desired. When cool, transfer the applesauce to an airtight container and refrigerate for up to 2 weeks.
