These crunchy oven fries are soul-satisfyingly good. Deeply crunchy on the outside and fluffy on the inside. Salty and garlicky and addictive and just totally French-fry-like. You make these with the skins still on, thereby keeping intact much of the potato's nutritional value. And you use healthy oils, thereby making the most of the grease factor.
We eat these with a lily-gilding Chipotle Mayonnaise: a third of a cup of Hellman's (or Best Foods) full-fat mayonnaise, whisked up with a scant spoonful of chipotle puree, a squeeze of lemon juice, and a bit of salt. Heaven.
If you didn't microwave them, I imagine that the potatoes would still cook through, but they'd be less fluffy inside, and if you try it, please let me know. Likewise, please let me know if you make these with sweet potatoes. Sweet potato fries are another favorite around here.
Heat oven to 475° F. Quarter the potatoes lengthwise, then cut each quarter further into 2 or 3 skinny, even wedges.
Combine the garlic and oil in a large bowl and microwave until the garlic is fragrant, about 1 minute. Pour off most of the oil onto a rimmed baking sheet, and tilt the sheet to coat it; you will leave behind the garlic with around 1 tablespoon of oil in the bowl, and this is just right.
Add the potatoes to the bowl and use a rubber spatula to toss and coat them with the oil and garlic. Wrap the bowl tightly in plastic wrap and microwave on high power until the potatoes are translucent around the edges, 3 to 6 minutes, shaking the bowl to redistribute the potatoes halfway through cooking.
Combine the cornstarch, salt, pepper, and cayenne in a small bowl. Sprinkle over the hot potatoes and toss well to coat. Arrange the potatoes in a single layer on the prepared baking sheet and bake, turning once, until deep golden brown and crisp, 30 to 40 minutes (I flip them after 15 minutes). Drain briefly on brown paper bags, then serve hot.