Combine the egg yolks and sugar and whisk until pale yellow and creamy.

Heat milk and cream over low heat, being careful not to scald. Temper the eggs by slowly whisk a small amount of the hot milk into the eggs. Continue whisking while adding about half of the milk. Once the eggs are tempered, the mixture can be added back to the pot of remaining milk. Continue to heat while whisking until the mixture starts to thicken. Remove from heat and add vanilla and spices. Add alcohol if you like. Pour into a bottle or pitcher and chill.