Mussels with White Wine

Name: Mussels with White Wine
Ingredients: 1 large egg yolk; 1 garlic clove, finely grated; 1 tsp (or more) fresh lemon juice; 1 /4 cup vegetable oil; 1 /4 cup extra-virgin olive oil; Kosher salt; 2 tbsp olive oil; 1 medium yellow onion, chopped; Kosher salt, freshly ground pepper; 2 garlic cloves, finely chopped; 2 tablespoons tomato paste; 1 /2 cup white wine; 4 pounds mussels, debearded, scrubbed; 2 teaspoons fresh thyme leaves; Sliced country-style bread, toasted (for serving)