Place the onion, red pepper, Scotch bonnet chiles, papaya, and garlic in a food processor. Pulse until finely chopped. Scrape into a large pot, and stir in the mustard powder, sugar, wine, vinegar, water, and lemon juice.

Bring to a simmer, then reduce heat to medium-low, and continue simmering, stirring frequently until the mixture has thickened, about 1 hour. Once thick, remove from the heat, and stir in the yellow mustard.