Bring a large pot of water to a boil. Add beans and cook for 5 minutes.

While beans are cooking, dice shallots and tomatoes. Slice bacon. Set aside

Make dressing by adding vinegar, mustard and seasonings to a jar. Mix together. Whisk in (or shake) oil.

Remove oil from pot and place in a bowl of ice water. Set aside.

Add vegetable oil to a cast iron skillet. Saute bacon over medium-high heat in a cast iron skillet. Add shallots once bacon starts to turn crispy. Cook just until shallots are transparent.

Drain bacon grease from skillet. Drain beans and add the beans into the skillet. Toss to coat so the bean pick up any leftover bacon fat.

Transfer to a large bowl. Add tomatoes. Drizzle dressing over top and toss to coat.

Can be served hot or cold.