Heat oil and butter in a medium-sized dutch oven over medium heat. Add cumin seeds and allow to sizzle until fragrant, about 1 minute. Add onions and cook, stirring frequently, until golden brown; about 10 minutes. Add jalapeno and ginger and cook 1-2 minutes. Add ground beef and cook, stirring to break up large pieces, until cooked through. Add spices (including cinnamon stick), potatoes and carrot, and enough water to cover by 1 inch. Cover and reduce heat to low; cook 30 minutes. Remove cover and continue to cook until most of the liquid evaporates and the curry is thick. Add peas and cilantro at the last minute, to preserve their bright green colour.

Meanwhile, preheat oven to 400 degrees. In a large bowl, whisk together flour, baking powder and salt. Cut in butter using a pastry cutter, two knives, or your fingers (work quickly if doing the latter, you don't want to warm the butter). Stir in the herbs. Add milk, and toss with a fork to combine. Transfer dough to a floured work surface and knead gently, 10-15 strokes. Roll out to 1/2 inch thickness, and cut rounds using a circle-shaped biscuit cutter or an overturned glass. Very gently re-roll out remaining dough scraps once more and repeat circle-cutting.

Place biscuit rounds directly on top of curry filling in dutch oven, overlapping in concentric circles. Fill in any gaps with leftover scraps of dough, tucking them under the more nicely formed circles to hide them. Transfer immediately to hot oven and bake 20-25 minutes, until golden brown.