Preheat your oven to 400°F. Peel and cube the sweet potato, then toss with a dash of salt, pepper, and the mixed herbs. Roast in the oven for about 20-25 minutes until tender and slightly caramelized.
Meanwhile, prepare the gnocchi dough by mashing the roasted sweet potato in a bowl. Add the whole wheat flour and the egg, mixing until a soft, pliable dough forms. Lightly knead on a floured surface until smooth.
Divide the dough into sections and roll each into a long rope. Cut into small pieces about 1-inch each. Optionally, press a fork lightly to create ridges on each piece.
In a pot of boiling salted water, gently drop in the gnocchi. They are ready when they float to the surface, about 2-3 minutes. Remove with a slotted spoon and set aside.
Season the chicken breast with salt, pepper, and a pinch of the mixed herbs. Grill or pan-sear the chicken until cooked through, then dice into small pieces.
In a small saucepan, melt the butter over medium heat. Allow it to froth and then turn a light brown as you add the fresh sage, swirling gently so the sage crisps up and the butter develops a nutty aroma.
Combine the cooked gnocchi and diced chicken on a serving plate. Drizzle over the sage brown butter sauce and gently toss to coat evenly.
Serve warm and enjoy this delightful balance of herbaceous gnocchi and luscious brown butter.