Combine vegetable broth and coconut milk in a saucepan.

Add chopped lemongrass stalk to the broth mixture.

Simmer the broth mixture over low heat to infuse the lemongrass flavor.

In a separate skillet, melt butter and sauté finely chopped onion until translucent.

Add arborio rice to the skillet with the onion and stir for 2 minutes to toast the rice.

Pour vermouth into the rice mixture and stir until absorbed.

Gradually add the warm broth-coconut milk mixture to the rice, stirring constantly.

Wait until the broth is fully absorbed before adding more, ensuring a creamy consistency.

Continue cooking the risotto over low heat until the rice is cooked through but still al dente.

While the risotto is cooking, heat a little vegetable oil in a separate pan.

Sauté the prawns in the hot oil until they are pink and cooked through.

Cut a portion of lemongrass stalks into fine strips, removing the outer leaves, for garnish.

Skewer the cooked prawns onto lemongrass stalks for presentation.

Just before serving, stir sour cream into the risotto to enrich the flavor and texture.

Serve the warm risotto garnished with diced granny smith apple, prawn skewers, and chopped lemongrass.