How to Make It
Properly burn toast. Take a slice of bread and spread with softened butter. Place it on a sheet tray and toast it in a oven set at 400°F until it’s dark brown, but not black. Let cool.
Make the burnt-toast gelato. In a medium bowl, whisk together the egg yolks and ¼ cup sugar. Set aside.
In a saucepan, combine the heavy cream, whole milk, milk powder, and remaining sugar. Bring to a simmer over medium heat, whisking occasionally. Pour a little bit of the liquid into the egg yolk mixture. Whisk to combine. Return to the saucepan and cook, stirring constantly until slightly thickened.
Whisk in the salt and crumble in the burnt toast. Allow to soak for a few minutes. Blend with a hand blender until smooth. Strain through a fine mesh strainer or cheesecloth. Chill completely before using.
Make the concord grape sorbet. Combine the grapes, sugar, and lemon juice. Allow to macerate for a few minutes. Blend with a hand blender until the grapes no longer look like grapes and the mixture looks like grape juice. Place the juice mixture in a saucepan. Add the water. Over medium heat, cook, stirring constantly, until the mixture boils. Carefully strain through a fine mesh strainer or through cheesecloth. Chill completely before using.
Combine the gelato and sorbet. Slowly pour the concord grape sorbet mixture into the popsicle mold, a little less than halfway. Carefully and slowly pour in the burnt toast gelato mixture. Do not stir, and move the mold as little as possible. (This gives you the swirl effect.) Insert the popsicle sticks and place the mold in the freezer. Freeze overnight.