In a small bowl, combine the apple cider vinegar, mustard, thyme and garlic. Season generously with salt and pepper, and whisk to combine. Whisk in the olive oil and hazelnut oil.

Steam the potatoes until just tender, about 10 minutes. Transfer to a large bowl and sprinkle 3 tablespoons of the dressing over the hot potatoes; toss to coat. Season with salt and pepper. Steam the snow peas until crisp tender, about 2-3 minutes. Transfer to a colander and rinse with cold water to stop the cooking (this will also preserve the color). Pat dry. Do Ahead: The salad can be made up to this point up to 2 hours in advance. Cover the potatoes and refrigerate. Store the snow peas separately in a ziptop bag or airtight container in the fridge.

Once the potatoes are cool, add the snow peas, red onion and hazelnuts. Pour 3 more tablespoons of dressing over the salad and toss to combine. Fold in the mint. Taste and season with salt and pepper. Let sit 10 minutes. Taste and add additional dressing if needed before serving (I usually add another tablespoon or two at this point—if you have leftover dressing, scrape it into a jar and save it for a salad later in the week). Enjoy!