Prep tofu: Pre-heat oven to 425°F (220°C). Tear tofu into bite-sized pieces. Melt 1 tablespoon of the butter in a large saute pan over medium heat. Add 1 teaspoon of the garam masala and 1 teaspoon of the cumin into the melted butter. Scatter in tofu and gently toss to coat. Spread tofu on a parchment-lined baking sheet. Bake until golden brown, 20 to 25 minutes.
Cook aromatics: Meanwhile, in the same saute pan (no need to wipe clean), melt the remaining 3 tablespoons butter over medium heat. Add onion and cook, stirring occasionally, until golden and soft, 3 to 5 minutes. Add garlic, ginger, remaining 3 teaspoons garam masala, remaining 1 teaspoon cumin, and turmeric. Cook, stirring continuously, until fragrant, about 1 minute.
Simmer: Reduce heat to medium-low. Add passata, water, cream, sugar, and salt. Stir to mix. Cover pan with a lid and simmer for 15 minutes for flavors to meld, stirring occasionally.
Combine: Add baked tofu to the curry. Stir to mix. Simmer uncovered for 5 to 10 minutes, stirring occasionally. Serve hot.
