For the crust: Grind oatmeal bars and almonds together using food processor or a mortar and pestle. Add melted butter and salt and press into bottom of a completely greased springform pan.
Bake for 10 minutes at 325˚. Let cool. Mix sugar and flour together and sprinkle over top of crust. (This prevents crust from getting soggy)
Prepare the water bath: wrap the bottom of your springform pan with a single sheet of foil, going all the way up the sides and fold over along the top edge or the springform pan. This will block water from coming in. Place the springform pan into a roasting pan and set aside.
For the filling: Beat cream cheese, mascarpone cheese, ricotta cheese and sugar in a large bowl until smooth. Beat in lemon juice, vanilla and almond extract. Mix in eggs one at a time. Pour cheesecake mixture into the springform pan overtop of the crust layer.
Fill your roasting pan with hot water, half way up the side of the springform pan. Here's a great video from allrecipes.com if you need some visuals for preparing a water bath for your cheesecake!
Bake at 325˚ until the center of the cheesecake is no longer wobbly when shaken, about 1hr and 5 mins. Let cool then refrigerate, preferably overnight.