Step 1

Line a 9- x 5-inch loaf pan with plastic wrap, leaving a 4-inch overhang on all sides. Beat heavy cream with an electric mixer fitted with a whisk attachment on medium-high speed until medium peaks form, about 1 minute and 30 seconds. Cover and chill until ready to use.

Step 2

Bring 1 inch of water to a simmer in a medium pot over medium. Place chocolate and coconut oil in a medium heatproof bowl; place bowl over simmering water. Cook, stirring often, until mixture is melted and combined, about 4 minutes. Remove bowl, and cool chocolate mixture 15 minutes.

Step 3

Meanwhile, whisk together eggs, sugar, mint, vanilla, and salt in another medium heatproof bowl; place bowl over simmering water. Cook, whisking constantly, until mixture reaches 165°F, about 18 minutes. Pour mixture through a fine wire-mesh strainer into bowl of a stand mixer fitted with a whisk attachment, pressing on solids to extract all liquid; discard solids. Beat on high speed until thick, fluffy, and room temperature, 6 to 8 minutes.

Step 4

Fold half of whipped cream into egg mixture. Fold in remaining whipped cream until just incorporated. Drizzle chocolate mixture over top, and gently fold into egg mixture, 2 to 3 times, to create a swirl. Pour mixture into prepared pan, and fold overhanging plastic wrap over top. Freeze at least 8 hours or up to 2 days. To serve, invert onto a plate, remove plastic wrap, and cut into slices.