Key lime pie without the guilt, or the Key

A friend, upon accepting my dinner invitation, quickly requested that I make her favorite dessert: Key lime pie.

While my mouth muttered "Sure, no problem," my mind thought "Uh-oh."

Truth is, I'd never made Key lime pie before. So I promptly headed to my cookbook collection to locate a classic Key lime pie recipe, figure its calorie and fat content, and then create a reduced-fat, lower-calorie pie that fit into my lean food plan and exceeded my guest's expectations -- a worthy but potentially difficult and maybe impossible task.

Scouring my reference books and food magazines for the definitive Key lime pie recipe not only turned up numerous recipes, but unearthed some general Key lime pie information.

Originally, Key lime pie used Key limes (well, duh!), a once-common Florida lime, one not usually found in today's supermarket produce sections. Key limes flourished in Florida until a 1926 hurricane destroyed the bulk of the state's Key lime groves.

Key limes (Citrus aurantifolia) are much smaller than Persian limes (Citrus latifolia), today's common lime found in supermarkets everywhere. Key limes look quite different than Persians, due to their smaller size and lemon-colored skin and interior.

Key limes also have more seeds, higher acidity, a stronger aroma and a much thinner rind than Persians. Today's Key limes predominantly grow in Mexico and Central America, where warm weather virtually guarantees no frost (ruinous to the variety).

Key lime pie purists insist there's a preferred flavor difference between pies made with Key versus Persian limes, also insisting that bottled and pasteurized Key lime juice pales in comparison to fresh-squeezed. I decided to use Persian limes in my pie, since locating fresh Key limes was nearly impossible.

Taking a look at the nutritional facts for whipped cream-topped Key lime pie surprised me. A slice delivered 270 calories (66.3 percent from fat) and almost 20 fat grams (more than half coming from saturated fat). Not for this lean guy.

Key lime pie filling combines lime zest, lime juice, egg yolks and sweetened, condensed milk (made from whole milk), with the filling thickening naturally from the reaction between the lime juice's acid, egg yolks and milk. Egg yolks and their total 20 fat grams had to remain, but today we have fat-free sweetened, condensed milk; trimming 30 fat grams and 270 calories.

Homemade graham cracker crust uses 5 to 6 tablespoons of butter. Supermarket-available, reduced-fat graham cracker crusts taste good, deliver 5 fat grams less per slice than homemade and cut 45 calories. Good deal.

Real whipped cream tastes great, no doubt, but for this pie the real thing also delivers 80 calories and 8.5 fat grams per slice. Fat-free, non-dairy whipped topping stands-in well for whipped cream and delivers just 45 calories and zero fat per slice.

Using these substitutions, I made my Key lime pie. The aroma of fresh-squeezed limes permeated my kitchen and whet my appetite

Once dinner moved from entrée to dessert I cut two slices and served one to my guest. I watched as she took her first bite, trying not to stare. Her eyes lit up and a huge smile broke across her face.

"This is the best Key lime pie I've ever tasted," she exclaimed. My smile equaled hers. I resisted telling her that she'd be smiling again the next time she got on her scale, since I'd saved her more than 100 calories.

Who'd ever think Key lime pie could be a guilt-free indulgence?

Easy and Delicious Reduced-Fat Key Lime Pie

4 teaspoons grated lime zest

4 large egg yolks

½ cup fresh lime juice (from about 3 to 4 limes)

1 can (14 ounces) fat-free sweetened condensed milk

1 reduced-fat graham cracker pie crust

3 cups fat-free nondairy whipped topping

Place oven rack in center position and heat oven to temperature directed on pie crust package.

While oven heats, make filling: In a medium glass mixing bowl whisk lime zest and egg yolks together for 2 minutes or until combined and green in color. Beat in sweetened, condensed milk until combined. Beat in lime juice and set mixture aside at room temperature to thicken, about 15 minutes.

For the crust: Remove crust's protective plastic cover, and follow directions for pre-baking. Cool on wire rack.

With oven rack in middle position, set oven temperature to 325 degrees.

Pour thickened filling into pre-baked crust, smoothing surface. Bake 15-17 minutes or until center begins to firm, yet wiggles slightly when jiggled. Cool pie on wire rack and then chill in the refrigerator for 3 hours.

Prior to serving, spread nondairy whipped topping evenly on pie.

Serves eight.

Cook's note: If you can locate Key limes, by all means use them in this recipe. They're small, so plan on spending more time squeezing them. In addition, keep in mind they'll probably produce a slightly less sweet result.

Nutrition values per serving: 167 calories (27.8 percent from fat), 5.2 g fat (1.7 g saturated), 24.8 g carbohydrate, trace amount fiber, 2.4 g protein, 107 mg cholesterol, 102 mg sodium.