In a large bowl, mix together the flour, sea salt and pepper.
Add the cubed beef and toss to coat (sirloin or NY striploin are best)
In a large, deep skillet melt together the butter and 1/2 tbsp. oil on medium heat.
Add the cubed beef and brown.
Remove the beef to a bowl. Add 1/2 cup of ale to the skillet and reduce heat to low. Scrape the browned bits off the bottom of the skillet and pour into bowl with beef. Refrigerate.
Add the other 1/2 tbsp. oil to the skillet. Add in the chopped onions and carrots. Cook on medium heat until the onions are translucent and starting to brown.
Add in the remaining ale, beef stock, Worcestershire sauce, brown sugar, bay leaves and thyme. Simmer for 1 hour to reduce. Stir occasionally. (Now is a good time to make the pastry)
Add in the mushrooms, garlic and lemon juice. Reduce for another 30 minutes. The mixture should be fairly dry.
Mix into the bowl with the beef. Refrigerate until ready to use. (Filling must be cool prior to placing in the pie.)
Preheat the oven to 425 degrees.
Take a little under 1/2 of the pastry dough and roll out on a heavily floured surface to 1/8" thick. Tip: run an icing knife under the pastry to separate it from the counter.
Fold pastry in half and then into quarters and unfold in a 9 inch springform cake pan.
Let the excess pastry hang over the edges of the pan and gently press down on the pastry to form it to the shape of the pan. Any holes are tears need to be repaired with excess dough or the filling will leak out.
Put the filling into the pie. Brush the top and inside edge of the pie with the beaten egg.
Take 1/2 of the remaining dough and roll out into a circle. Place on top of the pie. Pinch the edges closed. Cut off the excess dough and mold all remaining dough into a ball, cover with plastic wrap and freeze for later use.
Brush the top of the pie with egg wash.
Cut three slits into the top of the pie to allow steam to escape.
Put the springform pan on a cookie sheet and bake for 45 minutes.
Remove the springform sides and bake for an additional 15 minutes. Place tinfoil over the top of the pie if it's becoming too brown.