For jam: Mix rhubarb and sugar in medium pot and let sit 2 hours; stir in strawberries, chopped almonds and lemon juice and bring to a boil. Turn flame to medium-high and cook jam until thick, stirring often, about 20 minutes. Remove from heat and cool to room temperature. Refrigerate overnight.
For sandwich: Heat cast iron skillet over medium flame. Mix butter and mayonnaise and spread evenly on 1 side of 2 pieces of bread. Place buttered-side-down in pan and top each with Wisconsin cheddar. Place 3 to 4 pieces crispy bacon over each bread slice as cheese melts. Toast third piece of bread in toaster. Remove from toaster and spread 1 tablespoon jam on 1 side and 1 tablespoon chunky peanut butter on other side. Place toast over bacon and carefully top with other piece of cheesy bacon bread. Press with spatula and cook until bread is deep golden brown. Remove from skillet and halve.