Melt two tablespoons butter in a 12-inch non-stick skillet set over medium-low heat. When butter stops foaming, add the lamb sausages and cover the skillet. Cook until sausages are browned on the bottom, 8 to 10 minutes. Flip the sausages, cover again, and cook until browned on the other side and cooked through, another 8 to 10 minutes.
Meanwhile, bring a quart of salted water to a boil in a medium saucepan set over high heat.
Add peas and cook until tender and warm, 1 to 2 minutes.
Drain the peas, reserving a 1/4 cup of the cooking liquid.
Transfer peas to a food processor along with 1 tablespoon butter and chopped mint. Process until smooth, adding in some of the cooking liquid until it has the texture of hummus. Season to taste with salt and pepper.
To serve, spoon some of the puree on a plate and top with a sausage, pea sprouts, a sprinkling of feta, and some pita triangles.
