Preheat oven to 375 degrees F (190 C) and line 2 baking sheets with parchment paper (as original recipe is written // use fewer or more baking sheets if altering batch size).
Thinly slice plantains with a mandolin for best results. They should be not quite paper thin but close (see photo). I tried using a knife to thinly slice, but the plantains didn’t crisp up as well.
Add to a mixing bowl and drizzle with oil* and salt. Gently toss with a spoon to combine. Then arrange in a single layer on the baking sheets, making sure none are overlapping or they won’t crisp up.
Bake for 18-25 minutes or until crispy and slightly golden brown, being careful not to burn. Rotate pans at the halfway point to ensure even baking.
Once out of the oven, sprinkle with a bit more salt and lime zest (optional) and toss. Let cool.
While chips are baking, prepare guacamole by adding all ingredients to a small mixing bowl, mashing with a fork, then stirring to combine. Taste and adjust flavor as needed, adding more lime for acidity, salt for saltiness, or garlic for bite/zing. Transfer to serving dish.
Serve guacamole with chips and enjoy. Store leftover guacamole covered in the refrigerator up to 3 days, placing plastic wrap or parchment paper on the surface (in addition to a lid) to help from browning. Plantain chips are best the same day. But store completely cooled leftovers at room temperature up to 3 days in a sealed container.
*If avoiding oil, you can try and omit, but the chips won’t get as browned and crispy. *Nutrition information is a rough estimate. *Recipe makes 2 cups chips and 1 1/2 cups guacamole.