Stir together ricotta, 1/4 teaspoon salt, and pinch of pepper in a bowl; set aside.
Heat a large skillet over medium-high heat. Add butter and oil; heat until butter has melted. Add asparagus, and cook, stirring, 1 minute. Stir in mushrooms. Add stock, and bring to a simmer. Cover, and cook 2 minutes. Uncover, and cook until asparagus is tender and bright green, about 2 minutes more. Add cream; cook until reduced and slightly thickened, 1 to 2 minutes. Stir in herbs and lemon juice. Season with salt and pepper; remove from heat.
Bring a large shallow saucepan of water to a simmer. Working with 1 egg at time, break into a cup, and slide egg into water. Cook the eggs until whites are set, 2 to 3 minutes. Using a slotted spoon, transfer eggs to a plate lined with paper towels to drain.
Spread ricotta mixture over bread slices, dividing evenly. Divide asparagus among slices, and drizzle with sauce. Top each with a poached egg. Season with salt and pepper. Serve immediately.
The eggs in this recipe are not fully cooked. It should not be prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.