Magic Chocolate Swirl Ice Cream

FOR THE ICE CREAM: Microwave condensed milk and white chocolate chips in large bowl until chips soften, 60 to 75 seconds, stirring halfway through. Remove from microwave and stir mixture thoroughly, until white chocolate chips are melted and fully incorporated, about 2 minutes, pressing chips against side of bowl as necessary to melt fully. Stir in sour cream, vanilla, and salt.

Using stand mixer fitted with whisk, whip cream on medium-low until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1 to 3 minutes. Stir one-third of whipped cream into white chocolate mixture until combined. Fold remaining whipped cream into white chocolate mixture until just incorporated. Pour ice cream base into freezable container.

FOR THE CHOCOLATE SWIRL: Place chocolate in 2-cup liquid measuring cup. Heat cream, corn syrup, oil, and salt in small saucepan over medium heat until mixture is steaming, about 3 minutes, stirring constantly to avoid scorching. Remove from heat and immediately pour over chocolate. Allow mixture to sit for 5 minutes, then stir until chocolate is melted and smooth.

Slowly pour chocolate mixture into center of ice cream base. Dip butter knife through chocolate to bottom of container and lift up, swirling as you lift. Repeat about 10 times, until chocolate is evenly swirled through ice cream base, being careful not to overmix. Cover and freeze until firm, at least 6 hours or up to 2 weeks. Serve.