In a large bowl, mix together flour, sugar and salt.

Add your cubed butter and cut it into the dough using a pastry cutter.

When butter and flour have come together forming little pea size clumps, mix in the water and vinegar.

Once everything is wet, gently knead dough with your hands until it all comes together and there is no flour at the bottom of the bowl.

Separate the dough into two pieces and wrap in plastic wrapping.

Refrigerate dough for at least an hour before using, or freeze up to 1 month.

Preheat your oven to 350 degrees.

In a small sauce pan set over medium low heat, combine the rhubarb, strawberries, sugar, and lemon juice.

Simmer mixture for about 5 minutes or until the rhubarb is soft and the strawberries have melted into a syrupy mixture. Remove from heat and cool completely.

Spray a regular pie dish with non-stick cooking spray.

Roll one of the pie crusts out to a roughly 12-inch diameter and transfer it to your pie pan. Snug it against the sides and corners of the pan, letting the excess hang over the edges.

Fill the pie with your filling.

Roll out the second pie crust to a roughly 12-inch diameter.

Using a pizza cutter or sharp knife, cut the crust into even strips about ¾-inch wide.

Lay half the strips horizontally over the pie, using the longer strips in the middle of the pie and shorter strips toward the edges, with a bit of space in between each strip.

Fold every other strip back on itself.

Lay one of the remaining strips of pie crust vertically over the pie so that it lays across the unfolded horizontal strips.

Swap the folded and unfolded horizontal strips: unfold the folded horizontal strips so they lay over the vertical strip and fold the strips running under the vertical strip back over top.

Continue with remaining strips.

Brush with egg wash and sprinkle sugar on top.

Place pie on a cookie sheet and bake at 350 degrees for 50 minutes.

Serve with a scoop of vanilla bean ice cream.