For the Cheesecake:

1. Preheat oven to 350°F. Have an 8.5 inch or 9 inch springform pan ready.
2. In a large bowl, mix together the crushed pretzels and melted butter. Pat into the bottom and roughly 2 inches up the side of the pan.
3. In a large mixing bowl, beat together the cream cheese and sugar until light and fluffy, about 3-4 minutes. Beat in the eggs, one at a time, for 1 minute each. Add the melted chocolate then add the beer and vanilla. Gradually beat in the flour.
4. Pour the batter into the crust then bake 45 minutes or until the center is firm to the touch (the middle will still move when the pan is shaken). Remove from the oven and cool 1 hour in the pan.
5. Carefully run a knife along the edge to loosen the cheesecake. Cover and refrigerate for at least 4 hours or overnight. Top with whipped cream (recipe below). Store leftovers in an airtight container in the refrigerator for up to 1 week.

For the Whipped Cream:

1. In a large mixing bowl (with whisk attachment if using a stand mixer), beat the heavy cream until thickened.
2. Gradually beat in the sugar and vanilla then continue beating until stiff peaks form (when you pull the beater up, peaks will form and not fall over).
3. Spread on top of cheesecake then garnish with chocolate shavings.