Brown-Butter Sponge Cakes

1. In a saucepan, cook the butter over moderate heat, swirling the pan, until the milk solids turn deep brown, about 5 minutes. Let cool.
2. In a bowl, whisk the eggs with the sugar and salt until pale. Whisk in the milk. Whisk in the flour and the brown butter until the batter is very smooth and uniform in color.
3. Pour the batter into the canister of a 1-pint whipping siphon. Seal the siphon and charge it with one N2O cream cartridge according to the manufacturer's instructions. Shake the siphon vigorously.
4. Poke 3 holes around the side of eight 8-ounce wax-coated paper cups and coat the interiors with cooking spray. Hold the siphon upside down and insert the nozzle into one of the cups. Gently press the handle to dispense the batter, using a circular motion to fill one-third of the cup. Microwave on high for 45 seconds, until fluffy and risen. Invert the cup onto a plate and let stand at least 1 minute. Repeat with remaining batter and cups.

Notes: Serve right away with ice cream and chocolate sauce.