1. Preheat the oven to 425°F (220°C). Line a large rimmed baking sheet with parchment paper or lightly grease it.

2. Rinse the baby potatoes and cut any larger ones in half so they are all similar in size.

3. Place the potatoes in a pot of cold, well-salted water. Bring to a boil and cook for 6–8 minutes, just until barely fork-tender but not falling apart. Drain well and let steam dry for a minute or two.

4. In a large mixing bowl, whisk together the olive oil, melted butter, Dijon mustard, whole grain mustard, honey, minced garlic, kosher salt, black pepper, and smoked paprika until smooth and glossy.

5. Add the warm, drained potatoes to the bowl and gently toss until every piece is well coated in the mustard mixture.

6. Spread the potatoes onto the prepared baking sheet in a single layer, leaving a little space between each one so they crisp instead of steam.

7. Roast for 20–25 minutes, turning once halfway through, until the potatoes are deeply golden with crisp edges and the mustard coating has caramelized into browned, flavorful bits.

8. Transfer the hot potatoes to a serving bowl. Sprinkle with chopped fresh parsley and drizzle with fresh lemon juice if using. Taste and add a pinch more salt if needed.

9. Serve immediately while hot and crispy.