Heat the oven to 190C / 375F. Line a 33 x 46 cm / 13 x 18 inch sheet pan with parchment paper.

Cut the ends off each plantain, then score the peel lengthwise in 3 to 4 strips with a paring knife. Peel back the skin with your fingers, using the knife to help lift stubborn spots since green plantain peel doesn't pull away as easily as a ripe banana.

Slice the plantains crosswise into rounds 1.5 to 2mm thick using a mandoline. This step decides whether your chips end up crisp or chewy, so take your time here.

Zest the lime into a large mixing bowl, then juice it into the same bowl. Add the olive oil, salt, and chili powder if using, and whisk to combine.

Add the plantain slices to the bowl and toss with your hands until every slice is coated in the lime-oil mixture.

Arrange the slices in a single layer on the sheet pan, leaving space between each one so they roast instead of steam.

Bake for 12 minutes, then flip each chip with tongs. Bake another 10 to 13 minutes, until the edges are golden brown and curling.

Remove from the oven and let the chips cool on the pan for 5 minutes. They crisp up further as they cool, so don't judge them straight out of the oven.

Transfer to a bowl and serve with extra lime zest on top if you like.