Special equipment: A spice grinder
1. For the niter kibbeh (spiced butter): Melt the butter in a small saucepan over medium-low heat, swirling occasionally. Stir in the ginger, allspice, fenugreek, oregano, turmeric, cardamom, garlic and onions and bring to a simmer. Simmer until the butter is clear and the milk solids remain on the bottom of the pan, about 30 minutes. Reduce the heat to low if the butter is boiling too quickly–if it burns it will taste bitter.
2. For the berbere (spice mix): While the butter is cooking, whisk together the chile powder, paprika, cayenne, ginger, salt, garlic powder, onion powder and nutmeg. Set aside.
3. Put the cardamom, coriander, fenugreek, allspice, cloves and cinnamon in a small skillet and toast over medium-low heat, shaking the pan regularly, until fragrant, about 4 minutes. Cool slightly.
4. Grind the toasted spices in a spice grinder to a fine powder. Add to the chile powder mixture and whisk to combine. Sift the spice mixture onto a piece of parchment paper, return to the bowl and whisk again. Return the pieces left in the sifter to the spice grinder and grind again as finely as possible; whisk into the spice mixture. Set aside.
5. To finish the niter kibbeh: Line a strainer with dampened cheesecloth. Skim the foam from the top of the butter and discard. Ladle the butter through the strainer, leaving behind the milk solids on the bottom of the pan.
6. For the braised beef: Put the beef in a medium nonreactive bowl. Combine 3 tablespoons of the berbere, 2 tablespoons of the niter kibbeh and the red wine in a small nonreactive bowl and mix into a paste. Scrape half of the paste over the beef and toss to coat. Set aside the remaining paste. Let the meat marinate at room temperature for 30 minutes.
7. Heat 1 tablespoon of the niter kibbeh in a medium skillet over medium-high heat. Add the beef and cook, tossing, until it just loses most of its red color, about 2 minutes. Transfer the beef to a plate using a slotted spoon.
8. Reduce the heat to medium. Add the bell peppers and cook, stirring, until just beginning to wilt, about 5 minutes. Transfer the peppers with the slotted spoon to the plate with the beef. Add 1 tablespoon of the niter kibbeh and cook until heated. Add the onions and cook, stirring, until softened, about 10 minutes. Add the remaining spice paste, the chicken broth and black pepper and cook, stirring, 1 minute. Add salt to taste.
9. Return the beef and peppers and any accumulated juices to the pan with the onions, and cook to heat through, about 2 minutes. Serve hot with injera.