Place the ready made pie crust into pie place, flute the edges and polk with a fork on bottom and sides before berries go in. Slice straberries, put blueberries and raspberries in the bowl with 1/4 cup of sugar set aside. Beat the eggs and mix the sugar through. Add flour, melted butter and heavy cream, beat thoroughly. Place all berries in the pie crust and add the egg mixture of top. Preheat the oven to 325, bake 1 hour and turn up heat to 350 for an additional 20 minutes. Check for doneness after 10 minutes, oven may vary. Mine usually goes for 20. Enjoy.
Chill to serve. I usually put fresh whipped cream on top.