Whisk together the sugar, flour, milk, eggs, and nutmeg. Let this sit while you prepare the fruit.
In another bowl mix the cut strawberries and rhubarb.
Place a pie plate with the single pie shell on a baking sheet. Pour the fruit into the pie shell and distribute evenly.
Pour the wet ingredients over the fruit. Fill to the top edge of the pie shell. Dot the diced butter over the top of the filling.
Bake on the baking sheet for 10 minutes at 425. Reduce the temperature to 350 and bake 1 hour or until fruit is tender. It may take longer. Fruit will be tender when poked with a knife. You may need to place a ring of foil around the edge of the pie shell if it starts getting too brown.
Remove from oven and let cool. Refrigerate until you are ready to eat! I prefer my piece cold like a custard pie but you can warm it and put a scoop of ice cream on top or a little strawberry jam!