Pour the oil into a medium saucepan over medium-high heat. When it shimmers, stir in the onion and garlic and sauté until tender and starting to brown, 6 to 8 minutes.
Stir in 1 tablespoon of the berbere, the tomato paste, ginger, and salt and cook until fragrant, about 30 seconds.
Stir in the lentils and 2 cups water, bring to a boil, then reduce the heat to low, cover, and cook, stirring occasionally, until the lentils are tender and the mixture is very thick, about 25 minutes.
Stir in the remaining 1 teaspoon berbere, taste, and add more salt if needed.
Serve warm or at room temperature, with pitas or other chips or crudites.
Refrigerate in an airtight container for up to 1 week.