Preheat oven to 350°. Line 8 jumbo muffin cups with paper liners, or spray with baking spray with flour.
In a large bowl, beat butter and brown sugar with a mixer at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition. Beat in vanilla.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. With mixer on low speed, gradually add flour mixture to butter mixture alternately with buttermilk, beginning and ending with flour mixture, beating just until combined after each addition. Fold in 1 cup strawberries and ½ cup pecans. Spoon batter into prepared muffin cups. Top with remaining ¼ cup strawberries and remaining 2 tablespoons pecans.
Bake for 10 minutes. Sprinkle with sanding sugar, and bake until muffins are golden brown and a wooden pick inserted in center comes out clean, 25 to 30 minutes more. Let cool in pans for 5 minutes. Serve warm or at room temperature with Strawberry Butter.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/strawberry-pecan-muffins-strawberry-butter/