Chill coconut milk cans in the fridge overnight.
Toast shredded coconut if using. Let it cool.
Open cans and scoop out only the thick white cream (about 1½ cups total).
Beat coconut cream and heavy cream with a mixer for 2–3 minutes until soft peaks form.
Add sugar, vanilla, and salt. Beat for another 2–3 minutes until stiff peaks form.
Gently fold in toasted coconut if using.
Pour into a loaf pan or freezer container. Smooth the top.
Cover tightly and freeze for at least 4 hours until firm.
Let sit at room temperature for 5 minutes before scooping. Serve immediately.