-
1
In a heavy-bottomed saucepan, combine the rhubarb with 1/3 cup sugar. Cover and bring to a boil over medium heat, then uncover and cook over medium-low heat until the rhubarb is soft and completely falls apart into a sauce when you stir it, about 12 minutes. Allow this rhubarb sauce to cool to room temperature.
-
2
In a metal bowl, combine the remaining 2/3 cup sugar with the eggs, egg yolks, and vanilla. Set the bowl over simmering water and, using a handheld mixer, beat this mixture at medium-high speed until it is thick and pale, 6 to 8 minutes.
-
3
Remove the whipped custard from the heat and continue to beat it with the handheld mixer for another 6 to 8 minutes, until it has cooled to room temperature.
-
4
In a separate bowl, whip the cream and mascarpone to stiff peaks, about 5 minutes. Gently fold 1/3 of the custard mixture at a time into the whipped cream until fully combined. Then, gently fold in the rhubarb sauce until it is partially mixed in-there should still be streaks; the mixture doesn't need to be uniform. Transfer this mixture to a 2-quart (or so) container, lightly press plastic wrap onto the surface to cover and freeze until completely frozen, about 6 hours (or overnight).
-
5
In a heavy-bottomed saucepan, melt the butter over medium-high heat. Continue to cook it, stirring frequently, until it has browned and smells nutty, about 6 or 7 minutes (it will foam a bunch in the process, which is fine, just keep stirring). Scrape the butter (making sure to get all the brown sediment) into a mixing bowl. Set it aside to allow it to cool down to room temperature.
-
6
Preheat your oven to 350u00b0 F. Once the butter is cool, stir in the brown sugar, salt, and vanilla extract until well combined. Then, stir in the eggs until just combined. (The mixture won't look smooth, but you don't want to over-mix it.)
-
7
In a separate bowl, stir together the flour, baking soda, baking powder, and candied ginger. Stir these dry ingredients into the wet ingredients until they just come together.
-
8
Form the cookie dough into 24 equal-sized balls (about 1 1/2 tablespoons each) and place them, evenly spaced, onto two baking sheets. Press each cookie flat. (I found my cookies really didn't spread at all during baking so I had to smoosh them down to proper thickness, but they may spread by themselves in a more humid environment where the dough is moister.)
-
9
Bake each sheet of cookies in the oven until they just barely start to harden, about 8 to 10 minutes. You want them to be fairly undercooked so they stay chewy. Transfer to a cooling rack.
-
10
If you want to eat all of your ice cream sandwiches immediately with friends (a highly-recommended way of eating ice cream sandwiches!), take out the semifreddo and let everyone scoop a big helping of semifreddo out and smash it in between two somewhat-warm cookies and chow down. To assemble the sandwiches to save for later, allow the cookies to cool to room temperature. Remove the semifreddo from the freezer and allow it to soften just enough so that it is easy to scoop. Sandwich a generous scoop between two cookies, press together lightly, wrap tightly in plastic wrap or aluminum foil and place back in the freezer to harden. Repeat with all of the cookies to make 12 sandwiches (you'll have some semifreddo left over-yum!). Keep them tightly wrapped in the freezer for up to a couple of weeks. Also, if your cookies aren't underdone enough, they might be tough to bite through without squirting all of the semifreddo out from between them. If this happens, don't worry! Just twist the two cookies apart and eat each as an open faced ice cream sandwich with half of the semifreddo on each.
