In a medium bowl, combine orange marmalade, 2 tablespoons of the olive oil, chipotle powder, cumin, cinnamon, salt, and pepper. Remove roughly half of this orange marinade/glaze to a separate small bowl and reserve for brushing over skewers while on the grill. Add turkey pieces to the remaining orange marinade/glaze in the medium bowl and fold to coat evenly.: The bowl will smell intensely of citrus and warm spice as you stir; take a moment to inhale the marmalade mingling with cumin and cinnamon , it signals a rich, layered glaze is forming. As you fold the turkey into the mixture, notice how the glossy sauce clings to the meat, giving it a shiny sheen that will caramelize on the grill. This contact time allows the sweet and smoky notes to begin penetrating the surface, improving flavor depth. One frequent mistake is skimping on mixing, leaving some pieces undercoated; make sure each piece is well coated to avoid bland pockets. Also, by reserving half the glaze you create two functions: one for marinating and one for finishing, which helps prevent raw meat juices from contaminating the brush used at the end.
Add onion pieces to a small bowl and drizzle with remaining 1/2 tablespoon of olive oil. Fold to coat evenly.: The light scent of olive oil against the red onion will soften the sharp sulfurous edge and prepare the layers to char evenly. Tossing gently ensures the oil settles into crevices, promoting even caramelization that yields sweet, softened onion rather than bitter char. Avoid overloading the onions with oil, which can cause flare ups on the grill and greasy texture; a light, even coat is what you want. If the onion layers are left tightly packed rather than separated, they may steam instead of char, so separate them fully for the best texture.
Add turkey, onion, and thin orange slices to skewers, alternating between each one. When adding the orange slices, fold each half-round in half, sandwiching it between the other pieces (see my photos). Sprinkle assembled kabobs with salt and black pepper, to taste.: As you thread the skewers, you will feel the interplay of textures, the firm give of turkey , the crisp snap of the red onion , and the supple bend of folded orange slices. This alternating pattern ensures every bite contains a balance of savory meat and citrus brightness. The sprinkle of finishing salt and black pepper at this stage pulls the flavors together and seasons surfaces that may lose some seasoning during grilling. Be cautious not to crowd the skewers; overcrowding prevents even heat circulation and can lead to uneven cooking. Also, folding the orange and sandwiching it reduces direct exposure to flames so it softens rather than disintegrates.
Heat grill to medium to medium-high heat, about 425° F. Make sure grates are scrubbed clean and then oiled (see Notes).: You should hear a faint sizzle when you set your hand near the grill and smell the clean, hot metal as it comes to temp. A hot, well oiled grate prevents sticking and generates those coveted char marks that add both flavor and visual appeal. Scrubbing removes residue that can impart off flavors, and oiling creates a slick surface so the glazed pieces slide rather than tear. One common misstep is grilling on too low heat, which causes the glaze to shroud and steam rather than caramelize; too high and the sugar in the marmalade will burn. Aim for that steady 425° F range for balanced caramelization without charring.
Place orange halves cut-side down and turkey kabobs on hot grill grates and cook for 4 to 5 minutes, or until distinct charred marks form. Remove orange halves to a serving platter. Flip kabobs over, brush half of the reserved orange marinade/glaze over the top of each kabob, and cook for another 4 to 5 minutes. Flip one more time, brush on the remaining orange marinade/glaze, and grill until turkey is cooked through, to 145°F. Total cook time will vary, more or less, depending on size of turkey pieces and actual grill temperature.: As the skewers hit the grates you will hear a lusty sizzle and smell citrus sweet smoke as the marmalade begins to caramelize. Visual cues are crucial here, look for distinct dark sear lines and a glossy glaze that starts to set without blackening. The technique of brushing in stages builds layers of flavor and creates that sticky lacquered finish. Use an instant read thermometer and aim for 145°F to keep the turkey moist; relying solely on timing risks overcooking. A common mistake is flipping too frequently which prevents proper searing; let one side develop those char marks before turning. Also watch for flare ups from the glaze sugar and move skewers briefly if flames get high.
Remove kabobs to the serving platter, along with the grilled orange halves for squeezing over the kabobs as desired. Let kabobs rest a few minutes, then serve while still hot.: When you lift the skewers off the grill the aromas intensify, releasing warm citrus and smoky spice. Resting for a few minutes allows juices to redistribute inside the turkey , ensuring each bite is tender rather than dry. The grilled orange halves will be fragrant and warm, perfect for squeezing a bright finishing splash of citrus that cuts through richness. Avoid serving immediately straight off the heat without rest, as the juices will escape and the meat can dry. Arrange the kabobs on a platter with the grilled oranges for a vibrant presentation that invites guests to squeeze to taste.