Browned Butter and Sage Beefsteak & Mascarpone Flatbread

2 beefsteak tomatoes, cut into 1/3″ slices, set on paper towel to drain slightly
1/4 cup unsalted butter
2 Tbsp fresh sage leaves, chopped
2 tsp freshly squeezed lemon juice
1 cup mascarpone cheese, room temperature
2 Tbsp grated Parmesan cheese
1/2 tsp kosher salt
1/2 tsp freshly ground black peppercorns
1 store bought flatbread, approximately 11 x 6”
Additional kosher salt to taste

Preheat oven to 400°F. Line a baking sheet with parchment paper and set aside.
In a small pan melt butter and heat until butter starts to smell nutty and just starts to turn light golden brown, approximately 2 – 3 minutes. Immediately take the pan off the heat, stir in chopped sage and lemon juice. Set aside and cool slightly.
In a medium bowl, mix together mascarpone, Parmesan, salt and pepper. Place flatbread on prepared baking sheet and spread the mascarpone mixture evenly on top. Arrange sliced beefsteak tomatoes over the mascarpone. Spread and drizzle the sage brown butter over top. Season tomatoes lightly with salt.
Bake until mascarpone has heated through, puffed slightly and lightly goldened at the edges, approximately 12 – 15 minutes. Let rest a minute or two before serving.