(Nutrition information is calculated using an ingredient database and should be considered an estimate.)
Cook pasta following packet directions. Drain, reserving 1/3 cup cooking water. Cover pasta to keep warm.
Meanwhile, whisk egg yolks and parmesan in a bowl. Set aside.
Heat Flora in a large, deep frying pan over medium-high heat. Add mushroom. Cook, stirring occasionally, for 10 minutes or until golden and tender. Transfer to a heatproof bowl. Cover to keep warm.
Meanwhile, fill a medium saucepan with cold water until 8cm deep. Add vinegar and salt. Bring to the boil over high heat. Reduce heat to low (water should still be simmering at edge). Crack 1 egg into a small bowl. Using a wooden spoon, stir water to create a whirlpool. Tip egg into water. Cook, stirring water occasionally to keep egg moving, for 3 to 4 minutes or until white is set and yolk is still soft. Using a slotted spoon, remove egg from water and transfer to a shallow bowl. Using a large metal spoon, skim foam from water. Repeat with 3 more eggs. Cover to keep warm.
Add garlic to frying pan. Cook, stirring, for 30 seconds or until fragrant. Add flour. Cook, stirring constantly, for 1 minute. Reduce heat to low. Gradually add milk, stirring constantly, until smooth. Stir in stock. Bring to a simmer. Remove from heat.
Add pasta, egg yolk mixture, reserved cooking water, mushroom and spinach to frying pan. Return to heat. Cook, tossing, over low heat for 2 minutes or until sauce is thick and glossy. Serve pasta topped with basil, poached eggs and extra parmesan.