Glazed ham with grape and rhubarb compote

Ingredients:

• 1 ham half, 3.5-4.5 kg, on the bone, fully cooked
• 3 large stalks rhubarb (about 0.7 kg), cut into 1 cm pieces.
• 3/4 cup sugar
• 450 g red seedless grapes, halved (about 3 cups)
• Half a small red onion, thinly sliced
• 1/4 cup grainy mustard
• 1 tsp finely chopped fresh thyme + sprigs for serving
• 1/4 tsp red pepper flakes
• 1/3 cup light brown sugar

Preparation:

1. In a medium saucepan, combine the rhubarb, sugar, and 3/4 cup water and bring to a boil. Reduce heat to medium and simmer until the rhubarb is completely softened, about 15 minutes. Strain through a fine-mesh sieve into a separate saucepan, pressing down on the rhubarb with a spatula to extract all the syrup; set aside. Set aside 1/2 cup of syrup for glazing.
2. Compote:
   
   Place 1/4 cup of the remaining rhubarb into the remaining syrup in the saucepan (discard the rest). Add half the grapes, onion, 1 tablespoon mustard, finely chopped thyme, red pepper flakes, and a pinch of salt. Bring to a boil, then reduce heat to medium and simmer, mashing the grapes with a wooden spoon, until they burst and the sauce thickens, about 12 minutes. Add the remaining grapes and 1 tablespoon mustard and simmer for another 6 minutes. Let cool completely. The compote can be prepared in advance, covered and stored in the refrigerator for up to three days..
3. Preheat oven to 175°C.
4. Ham:
   
   In a bowl, combine the brown sugar and remaining 2 tablespoons mustard with the reserved 1/2 cup rhubarb syrup; set aside. Remove the skin from the ham and trim off most of the fat, leaving a 1/2-inch-thick layer. Make 1-inch-wide slits in the fat in a grid pattern. Place the ham flat side down on the rack in a roasting pan. Add 1 cup water to the roasting pan and cover the ham with foil. Bake for 1 1/2 hours.
5. Increase the oven temperature to 190°C (350°F). Remove the foil and brush the ham with the rhubarb-mustard syrup. Continue baking, brushing with syrup every 15 minutes, until golden brown and glossy, about 1.5 hours more. Transfer the ham to a platter and garnish with thyme sprigs. Serve with grape and rhubarb compote.