Roasted Bone Marrow Recipe

Preheat and prepare bones

Preheat the oven to 450°F (230°C). Rinse marrow bones under cold water and pat dry with paper towels. Place bones cut-side up on a rimmed baking sheet lined with foil or parchment.

Season bones

Sprinkle each marrow bone with kosher salt and black pepper. Lightly rub the BBQ spice mix over the exposed marrow pieces so they have a thin, even coating. Tuck thyme sprigs between bones if using.

Roast marrow

Roast in the preheated oven for 15–20 minutes, until the marrow is bubbling and the edges begin to brown but not fully collapse (timing depends on bone size). Keep an eye to avoid melting away all marrow; it should be soft and spoonable.

Rest marrow

Remove from oven and let bones rest for 3–5 minutes. The marrow will firm slightly and be easier to spoon out.

Cook onions low and slow

While the oven preheats (or up to 2 days ahead), melt butter with olive oil in a heavy skillet over medium-low heat. Add the thinly sliced onions and a pinch of salt. Cook, stirring occasionally, until onions are deeply softened and beginning to brown, about 20–30 minutes.

Caramelize and flavor

Raise heat briefly to medium and add the brown sugar; stir and cook 1–2 minutes to dissolve. Add balsamic vinegar, Dijon mustard, and 2 tablespoons water. Stir and reduce heat to low; simmer until jammy and thick, about 5–8 more minutes. Taste and adjust seasoning with up to 1 tsp salt and 1/2 tsp black pepper. If making ahead, cool and refrigerate; gently rewarm before serving.

Prepare toasts

Slice the rye ciabatta into 1/2 inch (1.3 cm) slices. Lightly brush each side with the softened butter or olive oil. Toast on a baking sheet in the oven during the last 5–7 minutes of bone roasting (or under a broiler) until crisp and golden, about 3–4 minutes per side under broiler—watch carefully to prevent burning.

Assemble

Spread a small spoonful of onion jam on each toasted slice. Spoon roasted marrow from the bones onto the jam-topped toasts (use a small spoon or knife). Sprinkle chopped parsley and a pinch of coarse sea salt over each portion. Serve with lemon wedges to squeeze lightly over the marrow if desired.

Serve

Serve immediately while marrow is warm and spreadable. Provide extra toast and jam on the side. Leftover marrow can be refrigerated and used on toast within 2 days.