Introduction: Grapefruit Mousse Pie

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Sometimes people don't want a very heavy or sickly-sweet dessert after a large meal.

I came up with a light, tart grapefruit mousse pie that satisfies a dessert craving without being overbearing.  Grapefruit isn't everyone's favorite, but I love the way the sweet and tart play with the complex, slightly bitter undertone.

The simple cracker crust balances the airy mousse, while the sweet and tart sanding sugar and grapefruit caramel topping provide an intriguing variety of texture.

There are a few steps involved, yes, but it's not difficult to make.  I think it's well worth the effort if you have guests who enjoy grapefruit.

You will need:

2 ruby red grapefruits
1 C dark brown sugar
3/4 C white sugar
1 T coarse sanding sugar
1 T corn syrup
2 1/2 C whipping cream
1/2 C cream cheese
1/2 sleeve ritz or saltine crackers
1 t vanilla extract
1/4 C plus 1/2 T butter
1 envelope unflavored gelatin
a few drops red and yellow food coloring
1/2 t citric acid

Step 1: Make the Crust

1/2 sleeve crackers (Ritz or Saltines)
1/4 C dark brown sugar
1/4 C butter
1 t vanilla extract

Preheat the oven to 400 degrees F.

Crush the crackers in your hands, then put them in the bowl of a food processor.  Melt the butter, then add it and the sugar to the crackers in the food processor.  Pulse several times until the crackers are broken up into crumbs.  Add the vanilla extract, then pulse a bit more.

This makes a small amount of crust.  You could double this if you want more crust; I didn't want to use much because I wanted the dessert to feel light.

Press the crust mixture into the bottom of a 9" round springform pan.  Use plastic wrap to keep it from sticking to your hands.  Bake the crust for 5 minutes or so, until you can smell it and it begins to turn golden at the edges.

Step 2: Prepare the Grapefruit Mousse

1 1/2 grapefruit
1 packet gelatin
1/2 C brown sugar
2 C whipping cream
red and yellow food coloring

Zest one of the grapefruits before you cut them.  I forgot to do this.  It's a lot harder after they've been cut up.

Put the zest in a small bowl and set aside.  Slice the skin off one of the grapefruits using a sharp knife.  Carefully cut the sections out, making sure to leave any pith or tough membrane behind.  Chop these sections and put them in the bowl with the zest.

Save any juice on the cutting board and pour it through a strainer into a small pan.  Squeeze the remains of the first grapefruit into the pan.  This might be slightly messy trying to squeeze the starlike shape of membrane.  Halve the other grapefruit.  Save one half for the caramel, and squeeze the other half into the pan.  

There are some sources on the web that say you can make stabilized whipping cream simply by adding some powdered gelatin to the cream itself before whipping.  This never works for me.  The cream might be stabilized, but I get chunks of gelatin in my whipped cream.  I don't know why I fell for this again.

Add the gelatin to the juice in the pan.  Let it sit for 10 minutes to bloom, then gently heat it until the gelatin is dissolved.  Set the juice aside to cool.  Pour it into the bowl with the grapefruit zest and segments.

Add 1/2 C brown sugar to the whipping cream, then whip it until it almost forms stiff peaks.  I added some food coloring because I figured the pale brown color from the brown sugar might be off-putting.  I used 4 drops of red and 2 drops of yellow.

Gently fold the grapefruit mixture into the whipped cream.  Once the mousse is thoroughly mixed, spread it evenly onto the crust and refrigerate at least a couple hours to let it set.

Step 3: Make the Caramel

1/2 grapefruit
1/2 C white sugar
1 T corn syrup
1/2 T butter

Squeeze the remaining half grapefruit into a pot.  This should give you about 1/2 C juice.  Add the sugar and corn syrup and bring to a boil, stirring occasionally.  Put the lid on the pot and boil for 3 minutes so the steam can wash down any sugar crystals on the side of the pot.  Add the butter and keep cooking on medium heat.

You might want to keep some ice water nearby.   Cook the caramel until it's just a bit thinner than you'd like when you drop it in ice water.  I think roughly 225 degrees F is a good temperature for this caramel to be used as a topping.  If you want yours thinner and easier to spread, cook it to a lower temperature.

I added food coloring to the caramel also; it was too pale without it, and I wanted the mousse pie to resemble a cut grapefruit.

Pour the caramel into a dish and let cool at room temperature.  If you miscalculated and the caramel gets too stiff as it cools, add a spoonful of water and stir (gently warm it if you can't stir it in).

Step 4: Pipe the Grapefruit Design

1/2 C cream cheese
1/2 C whipping cream
1/4 C brown sugar

Soften the cream cheese.  Whip it together with the whipping cream and brown sugar.  When it's smooth enough, scoop it into a small ziplock bag and snip the corner.

Remove the mousse pie from the fridge.  Run a knife around the edges, then remove the ring from the springform pan.  Pipe a circle of cream cheese mousse around the outside edge of the pie.  Keep piping until the white circle looks thick enough to be the white pith in a slice of grapefruit.

Pipe a starlike shape in the center.  Pipe lines from the outside circle toward the center of the pie to look like the membranes in a slice of grapefruit.  Use a butter knife to smooth the white mousse and to thin out the lines.  

The caramel should be thick enough to be slightly chewy by now.  This texture is a great contrast, but it does make it hard to spread on the pie.  Carefully drip some from a spoon into each section created by the cream cheese mousse.  Thin it with a little water if it's still too hard to work with.  Dip a clean spoon in water to gently spread the caramel into place.  It'll settle a bit and smooth out on its own.

Pipe cream cheese mousse around the outside edge of the pie.  Smooth it with a knife.

Step 5: Add the Tart Sugar Coating

the rest of the white sugar, let's say 1/4 cup or something
1 T coarse sanding sugar or turbinado sugar
food coloring 
1/2 t citric acid powder

If I'd thought of it ahead of time, I'd have added the red food coloring to the citric acid, mixed the yellow in with the regular sugar, and then added the red sour crystals to the yellow sugar.  Instead, I mixed yellow food coloring (with just a touch of red; grapefruit skin is often yellow) with the sugar, and then mixed in the citric acid.

This part was messy for me because I'm not very coordinated.  I ended up cutting a hole in the ziplock bag and sprinkling the sugar around the outside of the pie.  Some landed on the top of the outside edge and most fell down onto the cutting board.  Then I found some flat kitchen implement and used it to scoop up and press the tart sugar against the sides of the mousse pie to cover them.

You'll want to serve the pie within a couple hours of decorating it.  Otherwise, the caramel might ooze or the sugar might melt... heck, I don't know.  When you serve this, cut along the white mousse lines.  The caramel will make a mess if you try to cut through it, since it's stiffer than the mousse underneath.  Keep that in mind (what size pieces you want to cut) when you decide how many segment lines to pipe on with the white mousse.

At any rate, this mousse pie should be refreshingly light and not too sweet.  Thanks for reading, and let me know or post pictures if you make your own.  I'd love to see!