Hello Nathaniel,
Harvesting fresh chili peppers from the garden is wonderful, but their heat can often be unpredictable and easily overwhelm a pot. Fortunately, you have several reliable culinary methods to bring the heat level down without sacrificing the depth of your flavor profile.
First, utilizing fats is one of the most effective approaches because capsaicin, the compound responsible for chili heat, is fat-soluble. Since you have dairy and coconut milk available, stirring in full-fat coconut milk, heavy cream, or plain whole-milk yogurt will immediately bind to the capsaicin and temper the burn. If you decide to use yogurt, temper it first with a small amount of warm sauce and stir it in over low heat to prevent curdling. Coconut milk is particularly well suited to vegetable curry and blends seamlessly into the sauce.
Second, adding starch and extra mild bulk helps distribute the spice across a larger overall volume. Dicing a potato or sweet potato and simmering it in the curry works exceptionally well, as the starch absorbs some of the cooking liquid and softens the intensity. You can also add other mild vegetables such as carrots, cauliflower, or peas to stretch the base.
Third, balancing the dish with a touch of sweetness and acidity can counteract the perception of heat. Adding a teaspoon or two of brown sugar, honey, or grated sweet apple alongside a small squeeze of lemon or lime juice can significantly neutralize the sharp spiciness on the palate.
Finally, if the addition of coconut milk or vegetables softens your background seasonings too much, simply bloom a little ground cumin, coriander, and turmeric in a separate pan with a splash of oil and stir them in. This restores the rich aromatic foundation without adding any extra heat.
I hope these adjustments help you rescue your dish and enjoy your harvest.