Melt butter in a small skillet.
Add cornstarch. Stir until a paste is formed.
Add the bouillon cube or paste, lemon juice, and turmeric. Mix thoroughly.
Stir continuously over medium heat until sauce thickens.
This sauce should be velvety smooth. If it curdles, place in a blender and process until smooth.
Good served with steamed cabbage, sauteed zucchini, potatoes, etc.