In a sauce pan over medium high heat add a drizzle of olive oil and shallots cooking for a few minutes until shallots start to soften. Stir in garlic, ginger and curry paste cooking for another 1-2 minutes then scrape into slow cooker. Put sauce pan back on heat.
Turn heat up to high. Add another drizzle of olive oil if necessary. Salt and pepper both sides of the chicken and add to sauce pan. Quickly sear each side of the chicken and add to slow cooker.
Drop carrots and lemon grass into slow cooker.
In a large bowl mix together broth, one can of coconut milk, sugar and fish sauce. Pour over chicken, carrots and lemon grass.
Toss in cilantro sprigs and kaffir lime leaves. Cook on high 3-4 hours.
One hour before soup is ready add one can of coconut milk and sliced mushrooms.
When ready to serve remove cilantro sprigs, lemongrass, lime leaves and chicken. Shred chicken with two forks or fingers. Return shredded chicken to slow cooker.
Scoop into serving bowls and garnish with chopped cilantro, green onions and a squeeze of fresh lime juice. Serve immediately.