Heat 1 cup brown sugar in a dry 10-inch heavy skillet over medium heat, stirring with a fork to heat sugar evenly, until it starts to melt, then stop stirring and cook, swirling skillet occasionally so sugar melts evenly, until it is dark amber. Do not burn!
Add 1 1/4 cups cream (mixture will spatter and sugar will harden, don't freak out!) and cook, stirring, until all of caramel has dissolved. Transfer to a bowl stir in vanilla. Cool to room temperature.
Meanwhile, bring half and half, remaining cup cream, and remaining 1/4 cup of brown sugar just to a boil in a small heavy saucepan, stirring occasionally.
Lightly whisk eggs in a medium bowl, then add half of hot milk mixture in a slow stream, whisking constantly. Pour back into saucepan and cook over medium heat, stirring constantly with a wooden spoon, until custard coats back of spoon and registers 170F on an instant-read thermometer (do not let boil). Pour custard through a fine-mesh sieve into a large bowl, then stir in cooled caramel.
Chill custard, stirring occasionally, until very cold, 3 to 6 hours. Freeze custard in ice cream maker (it will still be quite soft), then transfer to an airtight container and put in freezer to firm up. Scoop ice cream in a small dish and sprinkle with bacon and a pinch of cayenne powder.
Short on Time? Go ahead. Use store bought vanilla ice cream, store bought caramel, blend them together, serve semi-soft with bacon sprinkles and a pinch of cayenne pepper.