Pulse onion, garlic, ginger, chile, 1 cup cilantro stems and leaves, and lime juice to a coarse paste in a food processor.
Heat coconut oil in a heavy-bottomed pot over medium heat. Add onion mixture and cook, stirring, 3 to 5 minutes. Add cumin, coriander, and turmeric and cook, stirring, another 1 to 2 minutes. Keep mixture warm over low heat.
Wipe out food processor bowl. Add ½ the cashews and grind to a fine paste. Add cashew paste, tomato puree, and stock to the pot with onion and spices and stir to combine. Bring mixture to a simmer over medium-high heat, then reduce heat to medium-low and cook, stirring occasionally, until liquid has thickened, 15 to 20 minutes.
Meanwhile, cook rice according to package directions.
Increase heat to medium and add shrimp to curry. Cover pot and simmer 3 to 4 minutes or until shrimp turn pink. Uncover, stir in peas, and simmer 2 to 3 minutes more. Taste and add salt and additional lime juice if desired.
Roughly chop remaining cashews. Portion basmati rice into 4 bowls and top each with equal amounts of curry. Garnish with chopped cashews and chopped cilantro.