Omurice (Japanese Omelette)

Name: Omurice (Japanese Omelette)
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: European
Ingredients: 1 tablespoon unsalted butter; ¼ cup|60 grams boneless, skinless, chicken thigh, diced; kosher salt and freshly ground black pepper, to taste; ½ cup|60 grams diced yellow onion; ½ cup|160 grams plus 1 tablespoon demi-glace, warmed; 2 tablespoons spiced ketchup; ¾ cup|110 grams cooked short grain rice; 3 large eggs; 1 tablespoon whole milk; 1 tablespoon heavy cream; 1 tablespoon canola oil