Dice the lard and place it in a casserole together with the garlic, cut lenghtwise into thin sticks, and the hot pepper. Brown well without oil; the fat of the lard will melt and will be partly eliminated. Add the white wine and allow to evaporate. Then add the red onions, and after a few minutes the tomato. Leave to cook for 30/40 minutes, until the water has evaporated leaving a smooth, nicely thick sauce. I reccomend preparing this dressing a day in advance. It will be tastier and more delicious. Do not add salt or pepper because the lard is already salty. Boil the spaghetti. Remove from the heat while still slightly firm, drain well, then add the sauce. Sauté, and sprinkle with as much grated sheep's milk cheese or Reggiano Parmesan as you wish. I suggest you accompany this dish with a wine that cleanses the mouth and stimulates digestion, such as the great sparkling wines or champagne, if possible rosé.