2 racks baby back ribs (about 5 lbs total)
6 tsp chopped fresh rosemary
2 ½ tsp kosher salt
3 tsp minced garlic
2 tsp red pepper flakes
1 jar (12 ounces) good orange marmalade
1 tbsp cider vinegar
Rinse ribs and pat dry. Place each rack of ribs on a sheet of heavy duty foil large enough to wrap around the ribs. Sprinkle ribs with 4 tsp rosemary, 2 tsp salt, 2 tsp garlic, and 1 tsp red pepper flakes; wrap in foil (meaty side down) making an airtight seal. Transfer to a rimmed baking sheet and roast in oven 1 hour 10 minutes. Turn the sheet half way through.
Meanwhile, for glaze, in a bowl, whisk together marmalade, vinegar, remaining 2 tsp rosemary, ½ tsp salt, 1 tsp garlic, and 1 tsp red pepper flakes. Cover and set aside.
Once ribs are done cooking in foil, unwrap them and place them onto a baking sheet lined with a cooling rack. Generously brush the glaze onto all sides off the ribs and place back into the oven uncovered until the glaze starts to bubble and brown. This should only take about 1 to 2 minutes. Once out of the oven, allow to rest for a few minutes, then cut and serve on a bed of rosemary (optional).