Measure the core ingredients: 1 cup rolled oats, 2 cups water or milk (or a combination), and 1/4 teaspoon salt.
Stovetop method — place the measured water/milk and salt in a medium saucepan and bring to a gentle boil over medium–high heat.
As soon as the liquid reaches a boil, reduce the heat to low, add the 1 cup rolled oats, and stir to combine.
Cook on low, stirring frequently, for about 5 minutes until the oats have thickened and most of the liquid is absorbed. Watch carefully and reduce heat if it starts to boil over.
Remove the saucepan from the heat. Stir in 1 tablespoon sweetener and 1 tablespoon flavoring, then stir in 1/4 cup nutrition add-in (chia, flax, hemp, or protein powder) if using. Portion into bowls and top or stir in up to 1 cup fruit and 1/4 cup nuts as desired.
Microwave method — use a microwave-safe bowl large enough to allow bubbling. Add the 1 cup rolled oats, 2 cups water or milk, and 1/4 teaspoon salt to the bowl and stir to combine.
Microwave on high for 2 minutes. Carefully remove and stir, then continue microwaving in 30-second increments, stirring after each increment, until the oatmeal looks slightly puffy and most of the liquid is absorbed.
Carefully remove the bowl from the microwave. Stir in 1 tablespoon sweetener and 1 tablespoon flavoring, then stir in 1/4 cup nutrition add-in if using. Portion into bowls and top or stir in up to 1 cup fruit and 1/4 cup nuts as desired.
If the oatmeal is thicker than you prefer, stir in a little additional water or milk to reach your desired consistency.
Serve warm. Allow to cool slightly before eating and enjoy.