My recipe is much simple. Makes one bottle:

5 eggs
1 can of condensed milk *)
250 ml of rum, vodka, gin, brandy, or whatever you fancy
milk, white wine or, in my case, dry mead to top up the bottle

*) That's "condensed", not "evaporated"; the latter is much thinner and less sweet. Real condensed milk is thick as honey and about that sweet. It usually comes in about 400 ml cans.

Separate egg yolks and whites. Use only the yolks. Use the whites to make some meringue or just dump them down the drain. Pour the vodka (rum, gin...), the yolks and condensed milk into the bottle. In that order (you can leave a little bit of vodka for rinsing the can of condensed milk and pour that in last). The bottle should be about 2/3-3/4 full. Give it a very good shake until nicely dissolved and smooth. Top up the bottle with milk (wine, mead...).

Consume within 2-3 days max.