Strain the heavy cream, milk, and coffee grounds mixture into a medium sized saucepan through a fine mesh strainer covered in a couple layers of cheese cloth (this can go a little slow-running a spoon around the grounds at the bottom can speed the process up a little).
Strain the 1 cup heavy cream into a medium bowl through a fine mesh strainer covered in a couple layers of cheese cloth and set aside. Place the fine mesh sieve (cleared of cheese cloth and coffee grounds) over the bowl and set aside.
In a medium bowl, whisk the egg yolks until smooth.
Add the sweetened condensed milk and salt to the saucepan with the cream and milk and heat on medium, stirring to combine. Continue cooking and stirring often until the mixture begins to thicken and bubble around the edges (about 3 minutes). Make sure it doesn't start to boil though.
Lower the heat to low and measure out one cup of the hot milk mixture and slowly pour it into the bowl with the egg yolks, whisking constantly. This is to prevent the eggs from cooking. Slowly pour the combined egg yolks and milk back to the saucepan, stirring constantly as you do so. Turn heat to medium-low.
Continue cooking until the mixture thickens (about 4 to 5 minutes). To test, dip a wooden spoon in and check to see if you can draw a clear line with your finger. The line should stay as it is and not loose its shape.
Pour into the fine mesh sieve over the reserved heavy cream and stir together.
Fill a sink with ice and cold water and put the bowl in it, bringing it to room temperature (about 15 minutes).
Cover and chill for at least 4 hours.
Place a loaf pan in the freezer. Transfer chilled custard to an ice cream maker and follow the directions of the manufacturer (this can take anywhere from 10 to 20 minutes in my experience)
Once done, quickly transfer the ice cream into the frozen loaf pan.
Cover with plastic wrap and freeze for at least 4 hours before serving.
Let the ice cream sit at room temperature for 10 minutes before serving.