1 teaspoon vanilla extract. 1 large egg. Lightly grease a doughnut (or muffin) tin and preheat the oven to 350F. Sift the flour, cocoa powder, baking powder and baking soda, and then whisk in the sugar, nutmeg and salt.
steam engine. An engine in which the energy of hot steam is converted into mechanical power, especially an engine in which the force of expanding steam is used to drive one or more pistons. The source of the steam is typically external to the part of the machine that converts the steam energy into mechanical energy.
1 There is such a thing as an external combustion engine. 2  A steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine. 3  The fuel (coal, wood, oil, whatever) in a steam engine burns outside the engine to create steam, and the steam creates motion inside the engine. There is such a thing as an external combustion engine. 2  A steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine. 3  The fuel (coal, wood, oil, whatever) in a steam engine burns outside the engine to create steam, and the steam creates motion inside the engine.