In small bowl, combine ricotta, 1 Tbsp honey, parsley, and red pepper flakes (if using). Whip ricotta by hand using whisk or with electric mixer for about 2 minutes, until ricotta is light and creamy. Set aside.

In skillet, heat 1 Tbsp olive oil on medium-high heat. Add mushrooms and cook until brown on all sides, stirring only very occasionally. Add soy sauce to deglaze pan; tip mushrooms onto plate and set aside.

In the same skillet, heat remaining 1 Tbsp olive oil on medium heat. Add leek slices and cook carefully for 1 to 2 minutes each side, turning with palette knife or cake spatula, until tender and browned. Remove from heat.

Spread ricotta onto baguette slices and top with mushrooms and 2 or 3 leek slices. Drizzle tartines with remaining 1 tsp honey and serve.