Add the oil to a large skillet and place it over medium-high heat for to minutes. Add the onions. Cook for 5 minutes, stirring occasionally. 

Add the ground lamb to the skillet and break it apart with a wooden spoon. Add the garlic, carrots, thyme, salt, and pepper. Stir well and cook 5 to 8 minutes until the lamb is browned, stirring occasionally. 

Add the butter and stir to combine. Cook for 1 minute.  

Add the flour and stir until well incorporated and there are no clumps. 

Add chicken broth, tomato sauce and Worcestershire sauce. Bring liquid to a boil then reduce to simmer. Add the fresh corn, frozen peas, and simmer for 5 minutes, stirring occasionally. Set aside. 

For the crust: 

Place the potatoes in a large pot. Cover the potatoes with water. Bring the water to a boil, then reduce to simmer. Cook until potatoes are fork tender (try not to overcook the potatoes), 10 – 15 minutes. 

Drain the potatoes in a colander. Place the potatoes into mixer or return to the hot pot. Let the potatoes rest for 1 minute to allow any remaining water to evaporate. 

Start the mixer in low speed and add the butter slowly, salt and pepper and stir until all ingredients are mixed. This can also be done in the cooking pot. Make sure there are no lumps if planning to use a piping bag. 

To assemble the Shepherd’s Pie:  

Preheat oven to 400*F 

Pour the filling into a baking dish or individual baking dishes. Try to not over fill so it does not bubble over into your over. Spread out into even layer. Pipe the mashed potatoes on to the meat. Carefully spread out into an even layer. 

Baked uncover for 25 to 30 minutes. Cool for 10 minutes before serving.