Place new potatoes in cold water. Bring to a boil over medium-high heat and continue to cook for 10-15 minutes, until potatoes are tender but not falling apart. Smaller potatoes will obviously cook more quickly than larger potatoes. Check doneness by piercing a potato or two with the tip of a sharp knife. It should slide in and out easily without much resistance. Drain potatoes and rinse with cold water. Set aside to cool. Potatoes can be prepared up to two days in advance. Store in the refrigerator.
Make the Garlic Aïoli: Mince garlic clove and let sit in lemon juice for 10 minutes or so to mellow out the raw garlic flavor. Add mayonnaise and olive oil. Season with salt and pepper to taste. Aioli can be made up to two days in advance. Store in the refrigerator until ready to use.
Butter each slice of bread. Place a layer of baby arugula leaves on top. Slice new potatoes into thin (¼ inch thick) slices and arrange artfully over the arugula. Salt and pepper the potato slices to taste. Spoon aïoli over potatoes (I like to place the sauce in the center between the two rows of potato slices) and scatter crispy onions or shallots and chives, microgreens and/or sprouts on top. Serve.
Calories: 458kcal | Carbohydrates: 76g | Protein: 9g | Fat: 14g | Saturated Fat: 3g | Cholesterol: 9mg | Sodium: 146mg | Potassium: 1812mg | Fiber: 9g | Sugar: 4g | Vitamin A: 215IU | Vitamin C: 86mg | Calcium: 59mg | Iron: 3mg