Warm the vegetable oil in a large heavy based skillet over medium-high heat. The oil should look fluid and shimmer lightly across the pan before the paste goes in.

Cook the red curry paste with the garlic, ginger, and lemongrass for about 2 minutes when using jar paste. Stir continuously until the mixture smells deeply fragrant and small beads of red oil appear around the edges.

Pour in the chicken broth and scrape through the skillet to loosen the concentrated paste. Let it bubble rapidly for 3 minutes, until the liquid has reduced by about half.

Stir in the coconut milk, kaffir lime leaves, sugar, and fish sauce, then add the chicken. The sauce should turn creamy orange-red as the paste blends into the coconut milk.

Arrange the chicken in an even layer, bring the curry to a simmer, then lower the heat to medium and cook for about 8-10 minutes. The chicken should be cooked through and tender, while the sauce reduces toward your preferred thickness.

Taste the sauce and adjust with more fish sauce for savoriness or sugar for sweetness. A balanced curry should taste savory first, warmly spicy next, with a rounded sweet finish.

Stir in the pumpkin and green beans, then cook for 3 minutes. Check the pumpkin with a paring knife tip: it should yield easily without collapsing, and the sauce should coat a spoon.

Take the skillet off the heat and fold in the Thai basil leaves. The residual heat will soften the leaves while keeping their aroma bright.

Spoon the curry over jasmine rice and finish with red chilli slices and coriander/cilantro leaves, if desired. The rice should catch the glossy sauce, while the garnishes add fresh color and a sharper finish.