In a large skillet, bring 1 inch of water to a boil. Add cauliflower and 1/2 tsp salt, cover and simmer until slightly tender, about 5 min; drain.

In same skillet, melt butter with 2 tbsp oil over medium-high heat. Add cauliflower, toss to coat and cook, gently turning occasionally, until tender and just turning golden brown, about 6 min. Stir in remaining 2 tsp oil, 1/2 tsp salt, the pumpkin seeds, garlic, ginger and mustard powder. Cook until garlic is softened, about 2 min. Transfer to a serving bowl. Garnish with pumpkin seeds, if desired. Makes 8 to 10 servings.