In a glass measuring cup, whisk together the raspberry syrup, Dijon mustard, and vinegars. Season with salt and pepper and slowly whisk in the olive oil. Add the garlic clove and whisk again. This makes about 1 cup vinaigrette, more than is needed for the remainder of the recipe; the vinaigrette will keep, covered and refrigerated, up to 3 days.
Salad and assembly
About 5 ounces cold bone marrow slices, extracted and soaked
Fine sea salt and freshly ground black pepper
1/4 cup flour
1 egg, beaten
1 teaspoon mustard powder
2/3 cup fresh bread crumbs
Olive oil or lard
10 to 12 cups mixed salad greens
1. Season the sliced marrow pieces lightly with salt and pepper.
2. Prepare 3 shallow dishes: 1 with the flour, 1 with the egg, and 1 with the bread crumbs. Season the beaten egg with salt and pepper and mix the mustard powder into the bread crumbs.
3. Dip the seasoned marrow slices into the flour, then the egg, and finally the bread crumbs, making sure each piece is very well coated with crumbs. If the marrow isn't well coated, it may melt as it cooks. Keep the marrow cool; if your kitchen is warm or your hands are too hot, the marrow will begin to soften. Return the bread crumbed marrow slices to the refrigerator to firm up.
4. Heat the oven to 200 degrees. Place a baking sheet lined with paper towels in the oven.
5. Set a small frying pan over medium heat and pour in enough olive oil to cover the bottom of the pan. When the oil is hot, add half of the marrow and cook until golden brown on both sides, about 2 minutes per side. Transfer to the baking sheet, sprinkle with salt, and keep warm in the oven.
6. Drain the fat from the pan, wipe it clean, and pour in more olive oil to fry the second batch of marrow. Transfer to the baking sheet and sprinkle with salt.
7. Trim, rinse and spin dry the salad greens, and then place them in a large salad bowl. Toss the greens with enough of the vinaigrette to coat. Divide the salad between the plates and top with the warm marrow croutons.
Each of 6 servings: 442 calories; 4 grams protein; 13 grams carbohydrates; 3 grams fiber; 42 grams fat; 3 grams saturated fat; 31 mg cholesterol; 4 grams sugar; 108 mg sodium.