Preheat the oven to 350 degrees.
Use a large bowl to mix the flour, sugar, baking powder, and salt.
Separate your eggs and beat the yolks into the mixture above.
Add the milk, oil and apples, and rhubarb. Mix it well and pour it into an already greased pie pan (9-inch pan).
Bake for 40 minutes or until the pie is ready - insert a knife in the middle, if it comes out clean, it's cooked.
Allow cooling slightly before serving.
Serve with ice cream.