How do you make red berry pie in runescape?

Redberries can be obtained just outside falador, via lumbridge.

as to making the pie:

1. Use Flour>Jug of water(becomes Pastry dough}
2. Use Pastry dough > Pie dish (becomes Pie shell)
3. Use Redberries > Pie shell (becomes Uncooked redberry pie)
4. Cook on a range (Use Uncooked redberry pie > Range). Will either become a redberry pie (edible), or burnt pie (non-edible; can be emptied so dish is not wasted).