If you prefer a deeper, more complex flavor, dry-toast the oats in the cooking pot over high heat, stirring and tossing constantly, until lightly toasted and fragrant, then remove from heat and proceed.
If making overnight oats, combine oats and water/milk in a medium saucepan or 3-quart saucier and let stand, covered, overnight (if using milk, let the oats soak in the refrigerator overnight). If not making overnight oats, combine oats and water/milk in the saucepan and proceed with cooking immediately.
Bring oats and water/milk to a simmer over medium-high heat, seasoning lightly with a pinch of salt. Reduce heat to maintain a gentle simmer and cook uncovered, stirring frequently but slowly, until porridge is well-thickened but still flows slightly, about 5 minutes for overnight oats and 20 minutes for un-soaked oats.
If oats are still too firm to your taste, stir in additional water ¼ cup (60ml) at a time, and continue cooking, until desired texture of oats is reached.
Scoop porridge into warmed bowls and top with a pat of butter and/or a splash of cream. Sprinkle brown sugar on top. Serve.
