Crispy Smashed Purple Sweet Potatoes with Miso Garlic Butter

These crispy smashed Japanese purple sweet potatoes are a showstopper side dish. Boiled until tender, smashed flat, and roasted until the edges are crunchy and caramelized, they get a final touch of sweet-savory miso garlic butter that melts into every crack.

The vibrant violet interior contrasts with the dark, blistered exterior, making them as beautiful as they are delicious.

Purple sweet potatoes have a naturally sweet, nutty flavor and a stunning violet hue that stays vivid even after roasting. Smashing them increases the surface area, so the edges crisp up beautifully while the centers stay creamy.

The miso garlic butter adds a savory umami depth that balances the sweetness, and the honey brings a touch of floral sweetness. This recipe is simple enough for a weeknight but impressive enough for a holiday table.

Ingredients

Why this recipe works

The key to perfect smashed potatoes is boiling them until they are just fork-tender. This ensures they are soft enough to smash without falling apart, and the interior cooks evenly. Smashing them with a heavy glass creates rough, lacy edges that crisp up in the oven, providing a delightful textural contrast.

Roasting at a high temperature, 425°F (220°C), is essential for achieving a crunchy exterior. The high heat quickly evaporates moisture from the surface, allowing the edges to become golden and blistered.

The miso butter, made with white miso, honey, and garlic, is added after roasting so it melts into the crevices without burning.

Notes and substitutions

Japanese purple sweet potatoes, also known as Stokes Purple or Okinawan sweet potatoes, have a drier, starchier texture than orange sweet potatoes.

They hold their shape well when boiled and smashed. If you can't find them, regular sweet potatoes or yams can be substituted, though the color will be different.

White miso paste is milder and sweeter than darker miso, making it ideal for this butter. If you only have yellow or red miso, reduce the amount to 1 1/2 tablespoons. The honey can be replaced with maple syrup or agave. Use unsalted butter to control the salt level, as the miso is already salty.

• Japanese purple sweet potatoes: Regular orange sweet potatoes or yams can be used, though the color will differ.
• White miso paste: Yellow miso paste can be used for a stronger flavor; reduce to 1 1/2 tbsp.
• Wild honey: Maple syrup or agave nectar will add similar sweetness.
• Unsalted butter: Vegan butter or olive oil can replace butter for a dairy-free version.

Equipment

• Large pot for boiling
• Baking sheet
• Heavy flat-bottomed glass or potato masher
• Small bowl for miso butter
• Pastry brush