Combine whole milk and heavy cream in a sauce pan. Heat for 1-2 minutes until hot. Turn off the heat.
Whisk together egg yolks, condensed milk, and granulated sugar. Add 1/4 cup of the hot cream into the egg mixture to temper the eggs. Mix the eggs and hot cream, and then pour that mixture into the sauce pan.
Add espresso powder and vanilla extract. Turn the heat back on and mix the ice cream base until well combined.
Continue heating the ice cream base until the cream reaches 170 degrees F. Use a candy thermometer to measure the temperature of the cream.
Pour the cream through a fine mesh sieve into a large bowl. This will get rid of any egg or milk solids in the cream.
Put ice cream base in the fridge for 6-8 hours or overnight.
Pour the cream into an ice cream maker and churn for 10-15 minutes.
While the ice cream is churning, combine the chocolate and coconut oil. Microwave in 20 second intervals until the chocolate is melted. Mix together.
After the ice cream has churned for 5 minutes, drizzle the melted chocolate into the churning ice cream. The cold ice cream will harden the chocolate.
The resulting ice cream after 10-15 minutes should be slightly harder than soft serve.
Spoon the ice cream into a freezer safe container and freeze overnight.