Combine all crust ingredients except shortening in a bowl; cut in shortening until mixture resembles coarse cornmeal.
Place in an airtight container, store in a cool dry place while preparing other fruit mixture.
In a bowl, toss the fruit with Splenda, cornstarch, lemon juice and zest; let sit for 20 to 30 minutes.
Preheat oven to 375 degrees.
Place butter in a cast iron Dutch oven (5 to 6 quarts), or a large cast iron skillet (what I use); place on stove to melt butter; remove from heat.
In a bowl, combine the Crust mixture with the water and mix until just combined; pat out dough until formed into a large round patty big enough to fit into bottom of skillet with a small amount up the sides.
Spoon the fruit mixture over the dough.
Place in oven and bake 30 to 40 minutes until dough is golden brown and risen, and the fruit is bubbly.