In a large pot add water and boil over high heat, add salt and then the green beans. Cook the green beans for only 2-3 minutes, until you reach your desired level of doneness. Do not overcook, the green beans should be done but not limp. Drain and rinse to stop cooking process.
Meanwhile melt the butter and olive oil together in a cast iron skillet over medium heat.
As soon as your butter melts and is hot add the slivered almonds. Toast the almonds for 2-4 minutes, and stir occasionally. You can toast until just lightly beige or until golden brown.
Toss the cooked green beans into the skillet and pan fry with the butter, oil and almonds until they are hot and fully coated.
Do not over cook, they should still be soft but not limp. Remove your cast iron skillet from the heat and add lemon juice.