1. Prepare an ice-water bath and set aside.

2. In a medium saucepan, heat milk and cream over medium-high heat. Scrape vanilla seeds from beans with the tip of a small knife into pan; add beans. Bring to a boil, and immediately reduce heat to a simmer. Let simmer gently for 10 minutes. Transfer mixture to a bowl set over ice-water bath and let mixture cool to 140 degrees.

3. In the bowl of an electric mixer fitted with the whisk attachment, add egg yolks and sugar; whisk on medium speed until light and fluffy, 3 to 5 minutes. Add cooled milk mixture and whisk gently to combine. Whisk in milk powder and add coffee beans.

4. Return mixture to saucepan and place over medium heat. Cook until mixture reaches 160 degrees. Transfer ice cream base to a bowl set over an ice-water bath until cooled.

5. Transfer ice cream base to a covered container and refrigerate for at least 8 hours and up to overnight. Strain through a fine mesh sieve; discard any solids.

6. Wearing safety gloves and protective goggles, open package of dry ice. Wrap dry ice in a clean kitchen towel and then in a bath towel. Using a rolling pin, smash dry ice into a powder, making sure there are no large pieces. Unwrap towels and shake dry ice into a large glass bowl; you will only need to use about 1 1/2 cups.

7. Pour ice cream base into the bowl of an electric mixer fitted with the whisk attachment. Turn the mixer on the lowest speed. Slowly add a very small amount of dry ice. Mix until dry ice is completely dissolved and vapors have cleared. Continue adding dry ice in small batches (to prevent the ice cream from becoming grainy), until all the dry ice has been absorbed.

8. Increase the mixer speed to the second lowest setting and mix until smooth. Using a spatula, quickly scrape the ice cream into a container. Transfer to a freezer until ready to use. Ice cream is best when eaten within 24 hours.