In a small saucepan, heat half-and-half to 175°.
Remove from heat; add lavender. Cover and steep for 20 minutes.
Strain, discarding lavender.
Return to the heat; stir in sugar until dissolved.
Whisk a small amount of the hot mixture into the egg yolks.
Return all to the saucepan, whisking constantly. Cook and stir over low heat until mixture reaches at least 160° and coats the back of a metal spoon.
Remove from heat.
Cool quickly by placing pan in a bowl of ice water; stir for 2 minutes.
Stir in whipping cream to form a custard.
Press waxed paper onto surface.
Refrigerate for several hours or overnight.
Fill cylinder of chilled ice cream maker and churn and/or freeze according to manufacturer’s directions.
Note: Look for dried lavender flowers in spice shops. If using lavender from the greenhouse or garden, make sure it is pesticide-free.