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Why This Recipe Works
- Par-cook & shake: A quick boil with baking-soda alkalizes the exterior, creating the micro-fissures that blister into ultracrisp shells.
- High-heat oven: 450 °F (230 °C) maximizes Maillard browning while keeping the centers fluffy.
- Herb timing: Adding rosemary halfway through prevents bitterness and keeps its perfume bright.
- Maldon finish: A final pinch of flaky sea salt adds a delicate crunch and bursts of brine.
- One-pan ease: Everything roasts on a pre-heated sheet pan—minimal dishes, maximum flavor.
- Make-ahead friendly: Par-boil and refrigerate up to 3 days; roast just before serving.
Ingredients You'll Need
Fingerlings are the darling of the potato world—small, slender, and naturally creamy. Their thin skins crisp beautifully, so skip any peeler and simply scrub. Look for a mix of colors—ruby, gold, and purple—for visual drama. If you can only find one hue, don’t fret; the flavor is identical.
Olive oil needs to be decent but not your $40 bottle. A fruity, everyday extra-virgin stands up to roasting and mingles with the potato starch to create that glass-like crust. Avoid “light” olive oil; you want flavor.
Rosemary should be fresh; dried needles taste like pine-scented dust. Strip the leaves from the woody stems, then give them a rough chop so they release oils without turning into bitter confetti.
Sea salt is used twice: kosher salt seasons the boiling water and the first roast; flaky Maldon or fleur de sel is showered on at the end for pops of salinity. Regular table salt dissolves too quickly and can over-season.
Baking soda is the quiet MVP. Just ½ teaspoon raises the water’s pH, breaking down pectin and creating the fuzzy exterior that transforms into shatter-crisp shells. Don’t skip it.
Optional extras: a fat clove of garlic, smashed, adds gentle sweetness; a pinch of crushed red-pepper flakes gives subtle heat; lemon zest brightens the finish. Customize to your mood.
How to Make Crispy Roasted Fingerling Potatoes with Rosemary and Sea Salt
Heat your oven & pan
Place a rimmed half-sheet pan (13×18-inch) on the lowest rack and preheat oven to 450 °F (230 °C). A screaming-hot surface jump-starts crisping the moment potatoes touch metal.
Par-boil with baking soda
Bring 3 quarts water to a boil in a large pot. Stir in 2 Tbsp kosher salt and ½ tsp baking soda. Add whole fingerlings; boil 8 min. Drain thoroughly and let steam-dry 1 min so surfaces dry.
Rough-up for maximum crunch
Return potatoes to the empty pot, cover with the lid, and shake vigorously 10 sec. The edges will turn fuzzy—those microscopic cracks become blistered crunch later.
Season & coat
Drizzle with 3 Tbsp olive oil, ½ tsp kosher salt, and a few grinds black pepper. Toss until every spud is glossy. The thin layer of oil conducts heat and encourages browning.
Roast cut-side down
Carefully slide the hot pan out, pour potatoes onto it, and use tongs to place each one cut-side down. Return to lowest rack and roast 15 min undisturbed.
Add rosemary & flip
Scatter 2 tsp chopped fresh rosemary over potatoes, flip each piece with a thin spatula, and roast another 12-15 min until deeply golden and the largest pieces feel tender when pierced.
Finish with flair
Transfer to a warm serving platter. While still sizzling, shower with ½ tsp flaky sea salt, an extra drizzle of olive oil, and optional lemon zest. Serve immediately for maximum crackle.
Expert Tips
Don’t crowd
If doubling, use two sheet pans. Overlapping potatoes steam rather than roast, killing crunch.
Preheat the oil
Let the oil shimmer on the pan 1 min before adding potatoes; the sizzle is your crisp insurance policy.
Overnight option
Boil and refrigerate potatoes up to 3 days. When ready, proceed from Step 4—dinner in 30 min flat.
Save the oil
The rosemary-infused oil left on the pan is liquid gold. Drizzle over grilled bread or whisk into vinaigrettes.
Listen for silence
When the sizzle quiets, the water has evaporated and browning begins—peek and flip accordingly.
Re-crisp in air-fryer
Leftovers? 375 °F air-fryer for 3-4 min resurrects crunch better than an oven.
Variations to Try
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Smoky paprika & thyme: Swap rosemary for 1 tsp fresh thyme leaves and ½ tsp smoked paprika for a Spanish vibe.
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Garlic-Parmesan: During the last 5 min of roasting, scatter 2 Tbsp finely grated Parmesan and 1 clove minced garlic; finish with parsley.
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Lemon-Dill vegan aioli: Blend ½ cup vegan mayo, juice of ½ lemon, 1 tsp zest, 1 Tbsp dill. Dip, swoon, repeat.
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Truffle luxe: Replace 1 Tbsp olive oil with white-truffle oil after roasting; top with shaved black truffle if budget allows.
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Spicy curry leaves: Use melted ghee instead of olive oil, add 8 fresh curry leaves and ¼ tsp Kashmiri chili with the rosemary.
Storage Tips
These potatoes are at their peak straight from the oven, but life happens. Cool completely, then refrigerate in a shallow airtight container up to 4 days. To reheat, spread on a sheet pan and warm in a 425 °F oven 8-10 min, flipping once. Microwaves save time but sacrifice crunch—avoid unless desperate. For longer storage, freeze par-boiled potatoes (before the final roast) in a single layer on a tray, then transfer to freezer bags up to 2 months. Roast from frozen, adding 5 extra minutes.
Frequently Asked Questions
Crispy Roasted Fingerling Potatoes with Rosemary and Sea Salt
Ingredients
Instructions
- Preheat: Place rimmed sheet pan on lowest rack and heat oven to 450 °F (230 °C).
- Par-boil: Bring 3 qt water, 2 Tbsp kosher salt, and baking soda to boil. Add potatoes; cook 8 min. Drain and steam-dry 1 min.
- Shake: Return potatoes to pot, cover, and shake 10 sec to rough surfaces.
- Season: Toss with 2 Tbsp olive oil, ½ tsp kosher salt, and pepper.
- Roast: Pour onto hot pan, cut-side down. Roast 15 min.
- Add herbs: Scatter rosemary, flip potatoes, roast 12-15 min more until golden and tender.
- Finish: Transfer to platter, drizzle remaining 1 Tbsp oil, sprinkle flaky sea salt (and optional zest or pepper flakes). Serve hot.
Recipe Notes
For even more flavor, replace 1 Tbsp olive oil with duck fat or ghee. Leftovers re-crisp beautifully in an air-fryer at 375 °F for 3-4 min.
