Toast cumin and coriander in a hot dry skillet until fragrant. Place in a mortar and let cool. Toast peanuts in a dry skillet until fragrant, remove from the pan and let cool. peel shallots, garlic, galangal and coriander roots, rinse as needed, trim as needed and cut everything into small pieces. Place everything in the mortar, add shrimp paste, lime zest and Thai chili and crushed all into a paste. Add peanuts and crush.
Boil coconut cream in a pot. Add peanut mixture, stir and season with lime juice, soy sauce and sugar. Peel potatoes, rinse and dice. Add potatoes to the pot and simmer for about 10 minutes until slightly thick while stirring occasionally.
Meanwhile, dice tofu. Rinse broccoli and cauliflower, trim and cut into individual florets. Add broccoli and cauliflower to the pot and simmer for another 5 minutes.
Rinse scallions, trim and cut diagonally into thin rings. Season to taste. Serve curry in bowls garnished with scallions.
Serve if desired with quinoa.