For the mushroom conserva, place the sliced mushrooms in a heavy-bottomed pot on low heat. Meanwhile, in a separate saucepan, heat two Tbsp olive oil over medium-high heat. Add shallots, fennel, garlic and thyme, and sweat until translucent. Add tomato paste and fennel pollen, then stir for one minute. Carefully add remaining olive oil and bay leaf and bring to 190 degrees. Remove saucepan from heat and pour hot oil mixture over the mushrooms. Stir to coat. Continue to cook on low heat, stirring occasionally until bubbles just break the surface (about 5 minutes). Remove from heat and allow to sit. After 30 minutes, stir in the olives, lemon juice, lemon zest, apple cider vinegar and parsley. Taste and adjust for acidity and seasoning. When cool, cover with additional olive oil, if necessary, and refrigerate. Use within two weeks due to this recipe’s low acidity.
For the crostini, slice the seeded baguette into ¼-inch slices. Brush with olive oil and grill at the last moment. They should still be soft at the center. Set aside.
To plate, warm the porcini mushroom conserva to room temperature and gently stack on the crostini. Garnish with fresh peas, crumbled chèvre, pea shoots, blossoms, fleur de sel and a drizzle of olive oil. Serve immediately.