MIX flour, sugar and salt in heavy saucepan. Add egg yolks; mix with wire whisk until well blended. (Mixture will be very thick.) Gradually whisk in 1/2 can coconut milk. Cook on medium heat 2 to 3 minutes, whisking constantly.
MEANWHILE, bring remaining coconut milk to simmer in small saucepan. Gradually add hot coconut milk to the flour and egg mixture, whisking until well blended. (Mixture might be lumpy. Continue to whisk until smooth.) Simmer 7 to 10 minutes or until very thick, whisking constantly. Serve warm.